Probably decreased battery life from "push" technology - more polling taking place. Still, probably not significant enough to cause any major issues for people and the original iPhone with 2.0 firmware is still going to have better battery life than the iPhone 3G (I recharge my phone every night and have yet to see the battery life go below 2/3rd full).

Gil - frankly, there's nothing on the market that works quite like the iPhone. It's unique in its user interface and the level of integration that it achieves between mobile/desktop/web connections. This is why it's selling so well and is so popular now (not to mention all the hype and the advertising that Apple is doing). As to whether it's the right piece of technology for YOU is a decision only you can make though. It truly may not be worth the hassle in getting one if another phone can serve your needs just as well.

This may be a useful list to peruse for some of the top smartphones that are out there now. Maybe another phone than the iPhone might be a better choice?