They already showed some pictures (on LFI and on screen during presentations) and despite color/artifacts (prototype, no RAW-profiles) sharpness was definitely on par with 39MP-backs + the very best Rodenstock/Schneider-lenses. This quality is simply in a different league than 35mm.
The MTFs also look not too different so this makes sense. In fact, the S-lenses seem to reach the quality of the best stopped down MF-SLR-lenses even at open aperture! Open aperture f2.5 is really fully usable, which cannot be said about MF-lenses or Nikon/Canon-glass with their 20+MP-beasts. Remember that these are the central-shutter-lenses, faster lenses will follow (although depth of field will be crucial).
The CCD is an entirely new design (first used in the H3DII-50) and because of the microlenses, the S2 will be about one effective stop faster, it has about the size of Prosumer-Full-Frame-SLRs, it's extremely rugged and quite fast by MF-standards (no DSPs but a custom-made ASIC as a processor) and of course the lenses are unique. MFDBs with microlenses (33x44mm -> 31MP: H3DII-31, P30...) are professionally usable up to 400/800ASA while a D3X goes about one stop faster (were talking about pro-standards) so it will be quite interesting to see what the new CCDs (the 31MP-backs use the previous, 4 year old Kodak-CCD-architecture) are capable of.
Internal processing and good looking JPGs will most likely be superior with the Nikon/Canons, but hopefully the S2-JPGs won't look as horrible as my M8-JPGs (6-8MP-DSLR-class...).
It's not going to be a super fast press-camera, but an interesting alternative for those who are not happy with the ergonomics of MF or IQ of 35mm.
Of course 30x45 is far from 645-full-frame, but MF is still mostly 36x48mm (which is more a different aspect-ratio than a different sensor-size) and bigger formats make some lenses extremely difficult to design (has anbody handled MF-zooms?).
We should be thankful that somebody invested this much money in an entirely new system, it won't be the pefect tool for everybody, but having a choice is always nice!