@lg1 I'd predict a big difference. Lots of those chotckas, especially metal ones will ring like a bell at one freq. or another. It's impossible to predict exactly what each of those will do.
Good diffusors will break up and disperse waves across mid and treble ranges. Bass traps are needed if breaking up bass nodes is a goal(they usually help and really can't hurt). You can see some pretty decent DIY diffusors on my system page. Cheers,
Spencer