I've lived in Orlando my whole life (until recently relocating to Cocoa Beach!) and I would strongly recommend NOT taking the turnpike!
1. Its WAY too expensive. I mean $20!? I took the Turnpike to Miami one time and won't do it again.
2. NOTHING to see. Granted, most highways are boring, but the turnpike is so boring it makes the drive even more miserable. I-95 you go through several cities and there is more to look at.
3. Traffic. Yes, I-95 has accidents and traffic back up, but it is a much bigger highway so it moves faster. An accident on the turnpike (two lanes) is awful. And the fact that exits are few and far between you're stuck. Much easier to get around an accident on a 6 lane highway and get on and off to go around.
I've done the drive from Orlando to Miami more times than I ever wanted, haha. Hope this helps!