I was having the same problem too. I bought my G set with 2.3.4 before update it to 2.3.5. I've tried many ways even reinstall the whole kies. But still can't connect my phone to my laptop.

yup...done restarting both the phone and laptop. Once connected, there's a notification that prompt me to search for a hardware installation. But it will fail in the end and said my hardware cannot be installed

I've noticed some problem with my camera. Sometimes it will freeze after taking pic and i have to forced close it. And when i try to open the camera again, it will come out a msg with camera failed. I can't do anything but have to reboot the phone before can use the camera again.

i think the battery life did improve a bit...otherwise i didn't notice any difference btw the 2 firmware. Btw, i updated mine thru OTA. Kies is just sux. And 1 thing, after i updated mine i can't connect my phone to my laptop anymore. Maybe compatibility issue. So update at ur own risk