Just sharing my experience here.

I upgraded to 3.0GM last week, but only used it for 2 days. Now back to 2.2.1 already. I am using the iPhone 3G (official unlocked Sing set).

Some observations using the OS3 GM during the 2 days:

1. The Internet tethering option will not be available if you are using Celcom (that's me). I tried with my wife's Maxis sim card (prepaid), and the option is there. When i clicked on the button, a message pop up saying i have to contact a Maxis number to enable internet tethering.

2. As i am using Celcom with limited data package, i cant find a way to disable edge setting. Meaning that i just cannot stop the data connection to the iPhone, which is not good if you are not on a unlimited data plan. The "put garbage text in APN settings" fix  does not seems to work. This is the main reason went back to 2.2.1 (for now) until the solution to this is available.

3. Copy and paste is very usable, used it a number of times during the 2 days.

4. Forgot to try out the language feature for Malaysia (Somebody above asked about the BM language). But i remember reading that Malaysia is one of the language supported in 3.0.

5. I just cant get the MMS to work (using my Celcom). The same MMS config worked fine on swirlyMMS before. Not very sure why.

6. As somebody asked above, i can confirm that the caller ID problem is no more with 3.0. Call in and incoming SMS will display the names correctly.

For now i think i wait for the 3.0 JB then only upgrade to the official 3.0. But for those who is with Maxis with the right data plan should have no issues with the upgrades.

Hope this info is useful to somebody out there.

I think the 3G can do video MMS, only video recording is exclusive to 3GS.

For BM keyboard, maybe ujoewong can try it, since i'm back to fw 2.2.1 already so cant try it out now.

@Ujoewong: great to know that MMS works on celcom, maybe my settings was wrong somewhere.