I actually thought the Bionic with the extended battery was much easier to hold. And with a TPU case you couldn't even tell. Personally I like a thicker phone. That is why I need a case on my Maxx.
If I didn't suffer from a severe case of upgrade-itis I would still have the Bionic. It was an awesome phone. And if the Bionic had taken a micro sim I would have never sold it. I would have swapped back and forth between it and my Maxx. It was just a PITA using a micro sim adapter on the fly.