I've been playing more with the SampleCell card, maybe I should start a new thread, really, but here are my initial thoughts after a few brief sessions:
As far as samplers go, it's really quite basic. There's a modulation matrix, but not a lot of interesting sources/destinations by the looks of it. It has tempo-synced LFOs which I like. The filter is only low-pass and quite dull sounding. It works for rolling off a bit of top end, but if I want squelchy analogue leads I'll definitely look elsewhere. Pitching things down sounds great on any sampler of course, and this is no exception. I don't know which interpolation algorithm it uses, but I'd say it has maybe a bit of crunch to it, but it's not a "character sampler" IMO.
I like the way you set up multis, load an instrument off disk or make a new one and set the channel. It's very straight-forward and nice to work with. The interface is obviously in many respects miles ahead of a vintage hardware sampler by virtue of the larger screen, and file management is fantastic, since you basically use the Finder to organize. I've not actually used software samplers much, but I have to admit it is a lot easier to keep track of what goes where than on my hardware E-mus and Yamahas.
The absolute killer feature is Turbosynth though, and the integration between the two. TS is offline, but you'd never know it with the SampleCell - if you turn on the auto-update samplecell option in TS, any time you save the output of a Turbosynth project, it's uploaded and ready to play, including updates to existing samples. It takes a second and causes a glitch if you're currently playing, but if you're not on stage or going live to tape it's as good as seamless, even on a 25 MHz Quadra 700 (although maybe with more complex patches the limited CPU will begin to show). TS is obviously an endless source of new digital waves and textures, and extracting envelopes from samples is also a pretty great feature. There's a lot of room for experimentation just with layering and different envelopes in the sampler I think.
I've been running TurboSynth, SC Editor, and Cycling 74 M as a sequencer in 20MB RAM with a little to spare (under 7.6). M sees the Samplecell directly through OMS, as will any other capable sequencer.
I've had a few glitches occasionally when reloading Samplecell banks after boot up, but no crashes and generally it feels quite dependable and responsive.