This is the harrowing procedure I went through while trying to use Samsung Kies to Upgrade my Samsgung Galaxy S from 2.2 to 2.3.3.
tl;dr version: Kies is crap. Don't use it if you can possibly avoid it
I used Kies a few months ago to upgrade my phone to 2.2. This phone is the replacement I got after Kies bricked the first one trying to do the upgrade but I put that down to the first one being faulty.
So I opened up Kies. The last time I opened it I had two monitors so when I opened Kies it positioned itself where the second monitor used to be (i.e. off the screen) and popped up a dialog box informing me that an update was available so I couldn't use keyboard shortcuts to move it. I had to plug the laptop into my tv as a second monitor to cancel the dialog box and move the window.
Once that was done I decided I should be on the latest version of Kies so I went to download the update. It thought about it for a second then told me I was on the latest version. The program can't decide if there's an update available or not.
So I said I'd just leave it the way it was and continue with the phone firmware update. I plugged the phone in, accepted the offer to upgrade the firmware and started the download. At about ten percent of the 3GB download I get an error: "The operation timed out". Google tells me this is very common when using Kies for firmware upgrades because Samsung's servers can't handle the load.
I tried maybe 10 to 15 times before saying I'd try it on my girlfriend's very old XP laptop (mine's on Vista). I had to install Kies on that which took about an hour and at one point I got the very helpful message "Installing .NET framework 4.0" followed by "Installing the .NET framework 3.5 may take some time etc etc". I assume they changed the framework version but forgot to update the message.
So I installed it and after a few unsuccessful attempts with a mixture of "could not contact information server" and "operation timed out" errors it managed to download the full 3GB. The phone switched to download mode as it's supposed to but when I did this a few months ago drivers started to install at that point and that didn't happen this time. The firmware upgrade hung at 0% for about ten minutes then said it couldn't connect to the phone. I decided to try again. "could not contact information server", "operation timed out" and finally it downloads it again (my internet download allowance is probably used up at this stage) but this time the phone doesn't even go into download mode and after ten minutes I get the error about not being able to contact the phone again.
So I decide to try the the first laptop again. "could not contact information server", "operation timed out" x5 and then it downloads it and the phone switches to download mode. The drivers start to install as expected but I don't think it's designed to handle waiting for the drivers to install while doing the firmware upgrade. The same thing happened that happened when my first phone got bricked: it got to 2% and hung there for 2 hours. When it works the whole process is supposed to take about 20 mins.
Eventually I had to turn the phone off. I get the dreaded phone computer exclamation mark error of a bricked phone, this error. But I haven't lost hope yet because there's an option for emergency recovery which I select. It hangs at 0% for ten minutes then says there's an error on the phone and quits. It tells me that I can try from another computer if I enter a recovery code it gives me so I plug it into the old laptop still in download mode and the drivers that didn't install last time immediately install. It's looking hopeful! Because this isn't the computer that did the original upgrade it has to download the recovery firmware. "could not contact information server", "operation timed out" x5. Eventually it downloads it. Because the drivers are already installed and it's already in download mode it finishes the firmware recovery successfully and to my surprise since this was supposed to be a "recovery" and not an "update" I'm now on 2.3.3.
And that kids is how you use Samsung Kies to upgrade your phone's firmware