In general use Wavelab is very stable. But I get crashes when exiting the program, resetting the master section, loading master section presets etc. This combined with the fact that Wavelab doesn’t necessary save master section presets when you tell it to is a massive killer for me. I’m mostly using UAD, DMG, Slate and Fabfilter mastering plugins. I have no issues with these plugins in Cubase or Pro Tools. I’m running 64bit iMac 3.5ghz. Same issue on both Mavericks and Yosemite.