Yeah... same observation here... I just had a look at their website for details and had a look at the (pre-) review of Sonic State about the Hydrasynth. Very interesting indeed. Regarding space, if the synth is indeed as nice as it seems to be, I think I go for the desktop one (saves me space and after knowing the thing I could put it in my 19" rack, just about enough space left), indeed missing then that ribbon and the poly-aftertouch however the desktop has 24 pads that compensates it a little bit I guess ;-)
For review reports of Eurorack modules, please refer to https://garfieldmodular.net/ for PDF formatted downloads