I don't have the MyTouch and therefore don't know the answer to your question. I just wanted to say welcome to AC. I came from the Blackberry world and considered the 8900 also. Did you not like it or did you just want a change?
We switched to T-Mobile because it cut our bill in half. We have five lines on our plan. I got the G1 because I wanted a change also. Like you, I have a BlackBerry 9530 unlocked lying around in case I need to fall back on it. However, I am having a lot of fun with the G1.