Originally Posted by Mrs Beanbag
Now that's just not really true. It may be that Blitz has a more efficient Bob engine than AMOS (I'd like to see some benchmarks though) but not all commercial titles rely on large numbers of bobs for their action, and even if that's what you want, AMOS's performance isn't that bad, and I can think of plenty of professional and highly regarded games that are less than silky-smooth. I reckon I could easily match Magic Pockets, for instance.
I don't know whether Blitz takes over the whole system when running or not, but quite a number of AMOS games don't close Workbench when running (I know this because they don't block the Amiga+A switching). Doing so would give a noticeable difference in execution speed of the AMOS game.
Dithell's Wonderland is a great example of a platform game that has a fair bit going on and runs really smoothly.