I was using Go SMS for a while actually, didn't really like it. Everything would get reset after I closed it through the task manager. None of the settings would save and it was really grinding my gears.
Those aren't the only problems I have with Go SMS. It's vibrate isn't as feelable or noticeable as stock sms. With Go SMS I could put my phone on my desk and not hear the vibrate, with stock sms its louder than if my phone was on loud.
Also, I can't get it to show contacts from the phone only, not the SIM card.
I like Go SMS but unfortunately I had to go back to stock, which is not bad eitheer. Go SMS turns my pictures sideways when I send them, unless I am doing something wrong, I would say that is a bug.