Sonnox SuperEsser VST2 (they don’t offer VST3) on OS X 10.11.6
There are some performance issues with this plugin on playback and rendering. When a certain amount of latency is reached, there will be an audio dropout near the start of playback, as well as near the start of a file rendering operation which is the ultimate deal-breaker.
Sonnox is aware of the issue and says it will be fixed in an upcoming beta and eventual maintenance update.