Interesting. I have both a Touch and a n810 and have come to some very interesting conclusions.

Speed: For web browsing the speeds are just about the same. The Touch is slightly more responsive while drawing, but usually takes longer to draw the whole page. The addition of flash on the NIT does affect a non-insignificant portion of the sites I frequent.

Stability: Safari is a crashing fiend. I can't run it for an extended period of time or open too many windows without it crashing. There is also a very subtle and annoying data loss bug that Apple doesn't like to talk about but is well documented on their site. The fact of the matter is that mobile safari takes the idea of "stateless" to a whole new level and will quickly become a thorn in the side of web application developers. The same pages under the NIT operate as I would expect from firefox.

UI: Hands down Touch, NIT's still have a lot of ground to make up if they even hope to come close.

I'm not saying there are not issues with the NIT, in fact just the opposite. I am an outspoken critic of the current state of os2008 as well as the general state of QA on the platform. On the other hand there is also the pink elephant in the room, that the next firmware for your iPhone could make you choose between the phone and the apps.