The Samsing 4.0 is a nice device with 1/2" more screen than my Touch. Stereo speakers and better cameras, GPS, microSD expansion, and FM radio make it worth the $30 premium over the $199 8gb Touch. Far better stock media support too. Audio (same songs through the same headphones from each) sounds about the same. Video is more impressive on the Samsung. Only the second Android media player I've tested that has the Android Market app on launch. It also came with a Samsung App Store app.
The Touch (4th gen) has a 960-by-640 screen while the Samsung 4.0 has an 800 x 480 screen. If you need more pixels than you can actually see then pick up a Touch. Something to be said for the larger screen
area though. Samsung's 5" version is also available ($269 for the 8gb version). No going back once you've had a 5" player, so be warned.
My review of the 4.0 is first up on my blog right now. Link in my sig.
4D