I'd love more info on play- it's been working great so far for me, though i've heard of issues on non macs.
I also love the sound of Fender amps so the fender specific amplitude is also very interesting to me. BGC- does guitar center have any of these programs set up for playing around with? I'd love to hear it before I dropped cash on it, and the guitar staff at GC tends to make me never want to shop there unless I absolutely have to.
Basically the infinite sustain guitar is for having super sustained melodic lines without the need for high gain or a huge delay loop. It'd be completely nuts with a slide I bet. Though the samples I heard were all pretty much straight clean tone, i'd love to hear it with a touch of gain and delay.
Overall a lot of cool stuff, as per usual.