Screen: Text on the screen is very sharp. The pixel density is very impressive. Whites and Blacks look fantastic for e-mail. As long as you are looking at it head on. Looking from the right edge or from the bottom, there's an almost unacceptable level of yellowing as soon as you leave perpendicular. I guess this is the cheapness of the display showing through, it's definitely not as nice as the IPS display in that device everyone is comparing the iPod Touch 2010 to. I checked out the screen with polarized sunglasses on and the see/don't see orientations are at about a 35 degree angle. For comparison, my iPad is 100% viewable (even in sunlight) in landscape mode, 100% dark in portrait mode.
Cameras: I took 2 still shots with it yesterday before giving up. Not expecting much at all from a .7mpix crapcam. A picture in decent light indoors was acceptable on the screen, as long as you don't try to zoom in.
Video does look better. It'll be useful in a pinch, but I wouldn't shoot a documentary or feature film on it.
Speed: It is very responsive. Things like the low amount of RAM should be easily fixable by enabling virtual memory once the jailbreak is out. It's obviously faster than my iPhone 3G and 3GS. I'd say that so far, it's on par with my iPad (to be expected)
iPod OK, this is what I actually got this thing for: a music player. I got the 64GB and still find the space lacking with a collection of Lossless audio. I was able to fit quite a bit of music on it, but still had a hard time picking and choosing what to put on the iPod playlist. I'm picking nits here though and was hoping that they would throw 2 of Sandisk's new tiny 64GB flash chips in it. Oh well, next time.
Listening with a pair of JH13's, sound quality from the built in jack is pretty good. Very crisp and clear, but this is to be expected from a flash based iDevice without 3G. I haven't tried it with a headphone amp and line out cable yet, but it should be the status quo for sound quality.
What impresses me most about the music functionality is more on the software and usability end. This is very good when paired with a nice sized touch screen and the higher resolution. One of the new "about time" features is playlist editing. There are still a few things lacking (streaming an itunes library to the device- none of the third party solutions work very well). New Podcast downloads finally work in the background. It'd be nice to see the device auto check for and download new podcasts once a day or so, like iTunes will do. This would be one more step towards breaking the chain between iPods and their associated computer.
Overall, as a music player with some extra features and app capabilities, I'd say this is a very good improvement over some of the older devices. It is NOT fair to compare it to the iPhone 4, they're on completely different levels. Apple dropped the ball on construction and the hardware end of things, but this is to be expected from a lower end consumer level device.
Are there better options for a well featured PMP out there? Probably not at the moment. Then again, I've drunk so much of Apple's kool-Aid that the RDF is strong in me.
Cheers.