Not very often - it all depends upon how much text I need to enter. If it's just a few key strokes then I use the virtual KB. If it's more than that I may use the physical KB. I don't find it all that bad. Any KB that size is going to be problematic. It's not meant for touch-typing!
Then again, I'm not a big texter. If I were I might feel differently.
Then again, I'm not a big texter. If I were I might feel differently.