I think you’re going to find some glitches in 10.5, too - but nothing nearly as horrid as in 9.X - just don’t want your expectations to be too high. 10.5 is still beta, after all… and HASH beta at that…
In regards to compositing software, I use AE, but that’s because I know it. It does everything I want it to, and although I wish it was faster in some respects, many of it’s tools are familiar to Photoshop users, and I like it’s paradigm. The node based compositors just seem a bit cumbersome to me, but then again, I’ve never really pushed to learn how to use them.
AE is probably the least expensive of the packages out there for compositing.
For sound, there are a few possibilities - it depends on what you want to do with them. Magix Samplitude is a very cool multi-tracker, Vegas Video is great for syncing SFX, and a lot of people use Sound Forge (Sonic Foundry makes both Vegas Video and Sound Forge) - although I find SoundForge very limiting in that it’s not a multi-tracker. If Magix Samplitude could bring in video, it would be my choice hands down.
Hope this helps…
JoeW