I had one for a while, they are awesome, much better than a laptop or those awful netbooks if you just use the web and don't need powerful programs. The 3G models have GPS built in, the wi-fi only doesn't.
I'd wait a few months, Apple might be releasing gen 2 before Christmas so the current ones will be cheaper, theres also rumors of a smaller version. If you do get one, they go on eBay for just a bit less than RRP anyway if you decide to sell.
Also I'd stay clear of other tablets coming out - iOS is awesome, it just works so well.