Omnigraffle 5.4 64-bit experience
 

I'm not that frequent a user of Omnigraffle, but, I do open, and sometimes edit slightly, some big (10-20 MB of elements), detailed/complicated files. Some of the files are created on Visio.

I just upgraded to Omnigraffle Pro 5.4 on Snow Leopard 10.6.8, and, tested it against my favorite files. It hasn't missed a beat yet. No performance issues, no flakiness, nothing to complain about.

Good job, Omni. Thanks!

Me too
 

Yeh, I haven't found an issue either. Omni support seemed confident that it would work with the newest mac and newest os. And it did just that.