Well I just bought the Keylab Essential 49, of course that's just 'essential' but everything works nicely as advertised. The only thing I haven't really tried is mapping the faders and knobs to other parameters than the pre-configured mixer and pan controls.
To back up ianpavy: I was actually looking in to buying a nektar keyboard because of the seemless Studio One intergration but didn't find one in my price range that still has a five-pin midi port, so I went for the arturia.
I think from reading reviews that the nektar keyboards have somewhat better build and durability but I am unable to confirm this.
Of course the Arturia comes with Analog Lab (that's 5000 somewhat tweakable, but very usable presets) and this plugin is also fully controllable from the keyboard (I mean the parameters, kinda like a very, VERY basic and superficial hardware synth/workstation)