By aspect — in detail
Good slim keys with a genuine rarity — monophonic aftertouch — but nobody mistakes them for full-size. The 37 Slimkeys are velocity-sensitive with mono aftertouch and an LED above every key (handy for seeing sequencer notes), and reviewers find the action pleasant and expressive for what it is. The universal caveat is size: this is a three-octave mini keyboard, fine for sketching chords and melodies but too compact for players who want to perform two-handed. There is no full-size or weighted option.
“this nice, springy action that lets you dial in velocity and aftertouch with precision”
Integraudio
“Mini keys unlikely to appeal to serious players.”
MusicRadar
Measured
Spec: 37 slim keys spanning three octaves, velocity-sensitive with monophonic (channel) aftertouch, an RGB-capable LED above each key, and octave transpose. No full-size or weighted-key variant.
The heart of the instrument, and the strongest reason to buy it — with one recurring asterisk. Four polyphonic sequencer tracks (up to 64 steps, 16 notes per step), a 24-part drum mode on Track 1, arpeggiators on the others, plus Scenes, Chains, a Looper and 16 step buttons make it a deep, fast, largely menu-free composing and performance tool that reviewers repeatedly call inspiring. The asterisk is MIDI-CC/knob control: there are only five touch-sensitive encoders shared across all four tracks, no per-track CC automation within sequences, and live MIDI-channel switching is slower than on the smaller KeyStep 37 — so as a real-time performance surface it's more limited than as a sequencer.
“The combination of structural arrangement features and deep real-time pattern tweaking makes the KeyStep Pro a versatile and inspiring performance sequencer.”
Sound On Sound
“This is easily one of the best do-it-all controllers out there right now.”
MusicRadar
“The sequencing on the pro is fast and super simple.”
u/Previous-Bug-5704 · r/synthesizers
“The Pro only has 5 - total!”
u/zacarycain · r/synthesizers
Measured
Spec: four sequencer tracks (Track 1 switchable to a 24-part drum sequencer, Tracks 2-4 to arpeggiators), 16 patterns per track up to 64 steps, up to 16 notes of polyphony per step; per-step Pitch, Gate, Velocity, Time Shift and Randomness; Scenes, Chains and a Looper; a separate Control mode where the five encoders send/automate MIDI CC. Only five encoders total, shared across tracks; no per-track CC stored within note patterns.
Connectivity
Strong consensus · 5 srcThe standout, and the clearest point of agreement — few controllers at any size match it. Alongside USB (class-compliant, and it can run standalone), it carries 1 MIDI in and 2 MIDI out, four voices of CV/Gate/Mod, eight analog drum gate outputs, clock in/out with a Reset out for Eurorack, a dedicated metronome output (with a built-in speaker), and a sustain input — and it outputs 1.2V/oct for Buchla as well as the usual 1V/oct. Reviewers routinely make this the headline. Minor gripes: the two MIDI outs are a duplicated port rather than two independent ports, and you can't route the mod strip or Control encoders to the CV mod outputs.
“It also of course wins big on connectivity, covering MIDI, USB, CV, triggers and clock!”
Sound On Sound
“the feature highlight here is the comprehensive range of ins-and-outs”
MusicRadar
“Its connectivity is a dream”
Integraudio
Measured
Rear I/O: 1 MIDI in, 2 MIDI out (a duplicated port, not two independent ports), four CV/Gate/Mod voices, eight drum gate outputs, clock in/out/reset, a metronome output with built-in speaker, a sustain-pedal input and USB. Outputs 1V/oct and 1.2V/oct (Buchla). Runs standalone; the mod strip and Control-mode encoders cannot be routed to the CV mod outs.
Integration
Moderate · 4 srcA solid, class-compliant play-and-sequence controller — not a deep DAW mixing surface. Over USB it's class-compliant, so it just works with any DAW (reviewers set it up in Ableton in minutes) and its Control mode does a reasonable job of generic transport/CC duties, while deeper configuration lives in Arturia's MIDI Control Center. What it isn't is a KeyLab/Launchkey-style surface with auto-mapped mixer and transport control; SOS points live players toward Novation's SL MkIII for superior MIDI-CC control and recallable templates. It's built to drive gear and sequence, not to run a mixing session.
“it was amazingly easy to set it up via USB MIDI”
Tape Op
“It does a decent job of generic DAW, plugin and CC control too, thanks to the customisable Control mode.”
MusicRadar
“as a live performance controller the mini keys and limited MIDI CC functionality might be an issue”
Sound On Sound
Measured
Class-compliant USB MIDI (no driver). Deep setup and project backup via Arturia's MIDI Control Center. No dedicated DAW auto-mapping scripts or transport/mixer surface; the Control track's five encoders are the CC-control provision.
Software
Thin evidence · 1 srcA modest extra, not a selling point. The KeyStep Pro ships with Analog Lab Intro (a taste of Arturia's V Collection sounds) and Ableton Live Lite — fine to get started, but nothing like the large bundles that come with Arturia's software-focused KeyLab/MiniLab controllers. You buy a KeyStep Pro for the hardware.
Measured
Bundle: Analog Lab Intro and Ableton Live Lite. No full V Collection or large plugin/sample library.
Portability
Moderate · 3 srcCompact for its capability, but not a featherweight. At 589 x 208 mm it's small enough to travel and not hog desk space, and it can bus-power over USB — though owners find powering from the included 12V supply steadier (see build). It's still a 37-key unit weighing a chunky 2.7kg, so it's portable rather than pocketable; a mini 25-key controller it is not.
“Compact at 589 x 208 x 38 mm, the KeyStep Pro nevertheless weighs a chunky 2.7kg.”
Sound On Sound
“the controller is small enough to transport easily”
MusicRadar
Measured
Dimensions 589 x 208 x 38 mm (chassis; 55 mm at its tallest), weight 2.7 kg / 5.95 lb. USB bus-powerable, and an external 12V power supply is included in the box.
Sources split, and it's the decision-relevant split — over dependability, not the chassis. The physical build is praised almost across the board: a solid, hefty unit with knobs and buttons that feel built to last. But reliability genuinely divides owners. One camp reports years of flawless, stable use and rates it highly; another hit the notoriously buggy 2020 launch firmware, lockups, dropped notes or CV outputs cutting out, and — in the worst cases — a unit that simply bricked. Two things make this actionable rather than a coin-flip: a major mid-2021 v2.0 firmware update resolved most of the launch bugs, and owners repeatedly find that powering from the included 12V supply (not USB) and backing up projects before firmware updates cures the instability. Buy where returns are easy, update carefully, and don't rely on USB power.
Measured
No formal reliability data exists. The physical build (metal-reinforced chassis, robust knobs/buttons) is consistently praised; the reliability signal is from owner/critical reports — buggy 2020 launch firmware (largely fixed by a mid-2021 v2.0 update), occasional lockups/dropped notes/dead CV outs, and a recurring pattern of bricking, which owners tie to USB power and firmware-update mishaps rather than to the build itself.
Where it splits
Solidly built and dependable — a premium-feeling unit that runs stably for years61%
“The build and visual/tactile interface of KeyStep Pro are super solid and next level.”
Tape Op
Buggy launch firmware and unit failures — lockups, dropped notes, and some outright bricked39%
“Since its debut in 2020, the Keystep Pro has seen minimal firmware updates.”
Integraudio
Broadly seen as worth it, and a genuine favorite — with rivals for pure sequencing. For its $499 list (often discounted toward $399) you get a feature set few controllers match at the size: four-track polyphonic sequencing, a 24-part drum mode, arps, and full CV/MIDI/USB connectivity in one standalone box, which is why it turns up on so many hybrid-rig desks and holds a 4.7/5 owner average. The counterweight: it's a real premium over the single-track KeyStep, dedicated sequencers like the Oxi One or Squarp Hapax outclass it for deep step-programming, and Novation's SL MkIII offers full-size keys and richer MIDI-CC control. What you're paying for is the connectivity and the immediate keyboard-first workflow.
“For melodic sequencing duties and flexible hardware control, this is one of the best devices on the market.”
MusicRadar
“Mini-keys be damned, this thing is the truth.”
u/trufus_for_youfus · r/synthesizers
