Just pushed through a job over the last few days. I feel like I've cut the cord between myself and FCP7 - now I'm deep into FCPX having to make it work for whatever I need to do. Of course, if I have to, I could step back to 7, but only if I have to.
It was a simple project - 2 cameras. I highlight these, turn them into a Multiclip; after some messing around get the audio from the track I wish to listen to; investigate the Angle Viewer and the Angle Editor and then I start cutting.
Multicam in the latest version of FCPX is a delight. Apple have not let us down here.
Easy to cut live and easy to dive back in and adjust shots as necessary. The "sync by audio" works.
Multicam in FCPX is responsive and it is easy to make work. I do admit I have only done a project with 2 cameras running, even so, first impressions count for a lot.