My biggest gripe with Galaxy S (at least the I9000) is that it doesn't do OTA firmware upgrade. It also needs Samsung Kies which runs only on Windows and on top of it fails to upgrade the firmware with a "Failed to convert to upgrade mode" message.
Official firmware upgrade is just too much of hassle on this phone.
It was indeed a horrible upgrade experience and it really blows my mind how Samsung can create such a great phone and so horrible Windows-software. If you want to give it another try, I covered how I got it working in this thread over at reddit:
It's thinner than an iPhone 3GS, about the same as an iPhone4
No keyboard, touchscreen is the best I've used.
The camera is good. Only downside is it doesn't have a flash - but the low light mode is surprisingly good.
The GPS is accurate (some people have had to change some settings to get quicker startup for it though)
It's not stock Android, but it's easily rootable (as in "install an app from the market and press one button)