I checked for the update while I was standing in line in the cafeteria at lunch time today. I would say that from first tap on the check for updates to the Congratulations screen, didn't take over 10 minutes. The upgrade completed flawlessly and painlessly for me. My Captivate is showroom floor stock, I've added a few apps in the month I've owned it, but nothing designed to unlock, root, or otherwise modify the basic package as delivered. Scored an 888 on Benchmark Standard. Not screaming, but not bad, IMHO.
After the completed update:
Firmware version: 2.1-update 1
Baseband version: I897UCJH7
Kernel version: 2.6.29 jetlaek.lee@sep-11 @2
Build number: ECLAIR.UCJH7
I've not noticed any issues with GPS before the update, so I don't know if it's improved or not. I can say that while outside after lunch, the phone showed me to be in one parking spot to the left from my actual physical location. So that's what.....12 feet off? I'm calling that acceptable for any application on the phone. Lock time was less than 20 seconds from when I opened Google Maps and tapped My Location.
All in all, I have nothing bad to say about the Captivate. I went from an iPhone 3gs to the Samsung Captivate, and I have zero regrets. For me, the Android OS beats iOS hands down in the little everyday things, like being able to customize the ringtones for email and text message notification, PROFILES, ease of data transfer between the phone and computer, standardized power/data/audio connector, not being tied to iTunes, and the ability to have a spare battery......just to name a few.
Not meant to be flaming Apple and/or the iPhone, just my personal observations. As always, do your research and YMMV.