I use the AAX version with ProTools 12 on a Macbook pro w/Yosemite.
I wanted a small plugin for LUFS monitoring of my STEREO mixes os mix elements (post-prod) on a light system, as I already have a bigger plugin on my pro station.
The plugin uses the latest ITU/EBU standards and gives us the most important informations, which is not always the case with other "not too costy" equivalent plugins: there was always something missing, but here all that is necessary is included: Range, True peak, Momentary, Short Term, Integrated loudness - all that is needed, and for a more than reasonable price!
I A/Bed it with its bigger brother Dolby MediaMeter and it doesn't pale to it, especially as it includes a realtime "normalization to -23LUFS" feature (don't know exactly how it works, I'll work on it).
Overall, it's a useful and small app which is also low-priced so don't hesitate provided you need it and know what you're doing . I recommend it to those looking for an introduction to the wonderland of loudness, and as a "low cost" (but no cheapish) alternative to Dolby's DMM (which price is a real scandal by the way!) or Waves' WMM for instance.