Why would you need voice and data at the same time? The only thing I could think of why you would Need it, would be if your just happening to be doing something on the data network, and you get a call. It'd be nice to not lose what you were doing.
Nonetheless, I'm an android boy. I have an incredible, I got it around the time it launched. It's been good to me so far, a few slip ups, and bugs here and there. But I don't think any smartphone will have no bugs or slips.