Aswain
3
I can speak from personal experience on this (though only two weeks worth). I have an A4 and recently picked up a used Keylab 25 as a dedicated controller. The Keylab series is a mixed bag. I think they have a reputation for lousy keybeds, but mine seems okay so far. They are very programmable (especially using Arturia’s software) and it’s nice to have dedicated programmable sliders in addition to rotary encoders at your disposal. My biggest nit to pick with this setup is it takes a LOT of fiddling to get a setup you’re comfortable with (I think, perhaps the Keylab is too configurable). Both the A4 and the Keylab have quite in depth programming structures. If you’re new to both at the same time, prepare to spend a lot of time pouring through manuals and troubleshooting dodgy behavior. For instance, just recently my Keylab has mysteriously begun sending a CC or NRPN signal to the A4 which results in a modulation command on the performance MIDI channel of the A4, and I’ve spent considerable time trying to track down why (still have no concrete explanation).
Bottom line: if you do not currently own one of the two devices, and it fits within your budget, opt for the Analog Keys if for no other reason than you will only have one manual to pour over rather than two.