I've just recently upgraded my 1.1.4 1st gen iphone 8GB to 2.0.2 >>

My iphone has only two screens of icons, maybe 3G of music, less than 100MBs of pictures or less and the rest is empty (never found anything worth installing..permanently)

1. Typing SMS and emails are slightly sluggish and slow.

2. Safari is much snappier and more responsive (previous 1.1.4 gets slowwwwwer when i open more than 2 pages at a time)

3. Discovery and switch to my home wifi seems to be much faster.

4. App store is a nice addition (bought 1 app... will probably get the Simcity game if it looks good -- http://www.macworld.com/article/132428/2008/03/spore.html

5. Remote app is dead easy and fun to use. (free app)

6. It takes slightly longer to restart on 2.0.2. ( I did that every night on my 1.1.4 -- dun wan people to call me when i sleep maaaa)

7. Sync takes slightly longer since iTunes 7.7 will now backup my entire iphone info (with all my free and paid apps)

With rumours thats swirling around about an imminent 2.1 update, I think the best option is wait and see... there might be plenty of goodies and some stability issues that will be ironed out. Or not.