I've been using Ozone a while now on mastering tracks.  I've had Fabfilter MB for a long time  (as part of a package) but never used it.  Just trying it out now in comparison to Ozones multiband compressor.   If any of you are familiar with both, I have a couple of questions :
 
1.   On each band Ozone has a make-up gain slider (also including auto-gain).  I don't see that in Fabfilter MB - is it the Output wheel (which doesn't appear to have an auto gain) - so meaning I up the output manually to have it approximately match the gain reduction of each band?
 
2. The attack and release in Fabfilter MB are in % not in ms.   Is there anyway to convert these % into ms -- eg, I'm trying to re-create an old Ozone setting  eg attack 10ms, release 100ms - is there a way to work out what is the equivalent in the Fabfilter MB's % ?

Pro-MB doesn't express envelope values in absolute time because they're variable, depending on what's happening with the input signal and the chosen filter slope. There actually is a makeup gain control, but it's labeled "output". Believe it or not, there is no need for a conventional makeup gain control with this plugin.
 
Pro-MB's controls are initially disorienting to users accustomed to conventional compressor terms, but that's because we're thinking of Pro-MB in a conventional compressor paradigm, which it doesn't fit into.
 
It's quite a different animal from a multi-band compressor such as Ozone's. You'll have an easier time embracing Pro-MB if you set aside everything you know about multi-band compressors and approach it as a different thing entirely.
 

Fab has several vids which will help blow your mind... also, grab the update