I own this reverb plugin more than year and use it a lot. The main reason is its fantastic ER engine. For me this is the best ER engine I have ever heart from VST reverb plugin. If you need to make unhearable depth and surround around any source material then try it and you will be surprised how quiet but efficient it can be.
Decay part of Masterverb algorithms is a little bit weaker than ER. There are Hall and Plate and for me they seems to be less effective and smooth I would expect.
Overal sound of WA Masterverb is warm and musical.
GUI is very nice and very easy to understand. There are a lot of parameters and graphic 3D screen for better and faster workflow. One feature I miss is stereo width and position feature. I hope it will be included in the next version.
There are a lot of useful presets and you can set your starting/default preset (what is still very unique but useful feature).
CPU load of this baby is near to nothing and you can use it offten as insert FX.
Customer support is fast and professional. I have never waited for answer more than few minutes.