I got one of those as an upgrade from Orange from a Sony K800i and the G600 is the worst phone I have ever used - absolutely awful, and my girlfriend who also got one agrees. Ours are now back in their boxes and I'm currently at war with Orange customer services trying to get them to take them back & let us exchange them for something better.
Issues we found:
* Very poor weighting, so as soon as you open the handset it is top-heavy and as a result we dropped them two or three times in the first ten minutes of using them.
* Very slow to do anything.
* Awful look and feel of menus.
* TERRIBLE camera - every picture we took, regardless of the lighting conditions, turned out blurry, even when we changed the camera settings. Also I took a photo of myself from arms' length in a darkened room and the flash barely reached my face!
* Poor signal strength compared to the K800i - tested this by having the G600 and the K800 on at the same time sitting on the sofa at home, and whereas the G600 had a low signal strength the K800 was at the maximum.
* Annoying functionality e.g. if you type a message, hit Send, and then close the slider the message doesn't get sent but instead goes into drafts, and it also strips out the destination from the message.
* REALLY annoying menu when typing a phone number, where you either get a picture of the Houses of Parliament with a fountain pen writing the number on a piece of paper, or if you turn this off you get a white screen where the numbers you type appear in huge multicoloured digits. No way to turn this off either.
Basically we hated our G600s...