I'm using 6230. It's working well and is just perfect with 770. It's small, the battery lasts long and it's also fast (Series 40). And as a bonus the phone seems to be lasting quite a lot of punishment (from 2 meters to concrete etc.). It's made to be used as a phone not as a multimedia terminal for which I have the 770. I think this combination is working a lot better then having a Communicator for example.