project bloat when working with compound clips

Hey there,
although I haven't yet tested myself fcpx on big projects, I have heard from different sources, including people from Leverage, that compound clips work poorly in fcpx, slowing down the app and or making it crash when used in big quantities; also it seems they behave badly when put into multicam clips... These would be some of the main reasons why people are using when working with dual-sound systems, instead of fcpx's built-in autosync features, the third party sync-n-link, which by the way goes through fcp7...
Can anyone comment on their experience with this? Do you have issues when working with hundreds of synched compound clips in a project?
I'm really curious about this, because if it is still true, it means that fcpx's autosync feature is basically useless...
I need some input on this issue as I am considering starting a big project for a feature film on fcp x, but I really don't feel sure about it . I might just go fcp 7 on this one and wait for at least a couple more updates before giving fcpx a chance in a truly high end professional environment.
Would surely appreciate all your thoughts on this one!

The main issue I have seen is cutting compound clips (like then sync'd clips) then putting those in a compound clip and then cutting that up, then doing it once more. I did. 25min short. All audio recorded sperately and sync'd. I edited off of all compound clips no problem. But I avoided compounding them again.

I am sure the project was larger than if I had just edited clips on their own. But I was happy with what I had. There were also whole scenes when I did the break apart function and it worked like a charm to really get into some channel mixing.