I agree with you. 64 MB is far too less.. I guess a cup of nescafe and a slice of cake costs more than the cost of 64 MB memory
64 MB USB Drive

May be the samples are compressed very well to enable a lot of stuff inside that 64MB without compromising quality. I know that the Roland`s have very good compression without compromising much on the quality Eg: G-70 has excellent sounds.. more than 1300 in their 192 MB of Waverom. But then again, it would be nice to have atleast 2 Expansion Packs/ atleast 512 MB of user sampling in the MOTL; the S650 allows one ExpansionPack so the 950 should allow 1.5 Expansion Packs

But overall, the audio stuff i.e. both styles and controls of pitch and tempo are cool features
If Bert Smorenburg does the demos for arrangers.. then surely, this will sound like top of the line