I bought this cheap in the sale a while ago and haven't gotten around to using it yet, primarily because I haven't had the time to dive in and learn it. But I am interested to see what kind of effect it will have on my sound, for better or for worse. 
 
I'm curious as to how most of you are using it though. Are you importing all of your stems completely dry into the Mixbus and starting your mix from scratch, or are you getting a good mix going within Sonar and then taking it into the Mixbus for some Harrison "polishing"? In other words, just using the Mixbus to get a bit of a Harrison sound (like the tape saturation)? 
 

I'm new to Mixbus as well, but I have been importing all tracks dry and starting the mix from scratch. Seems like that would be the best way to tell what Mixbus can do. So far, I am very satisfied with the results.

I have done it both ways and I prefer the the later. Using it for Tape Saturation, and it has a nice warmth to it.

But doesn't the tape saturation really only make a difference when you have a compressor after it? That's what I was led to believe from watching this video last night:

I am a bit of a regular user now so I can give you my ideas. I use Studio One and create all the music there and get it to the point of not doing anything more to the music but just about to mix.
 
I create stems of the buses and some tracks. Leave any broad based EQ alone and do that in Mixbus. Also you can afford to not use dynamics either on tracks and buses (in your DAW) because you can do that inside Mixbus too. I am not a fan of the limiter or compression much on the masterbuss. Leave that for a mastering session later.
 
You may want to print any reverb returns as well as special surgical or special tone shaping EQ in your tracks or stems before hand. Many of your VST's will open up inside Mixbus. You could still add the reverbs there too if you wanted too but I am not at this stage. They make a classy reverb too but it means buying it.
 
Mixbus will just bring the tracks and stems mainly together and it sounds fabulous doing it. Tape Sat can be used although the trick is to not get that smashing or distorting. Use it mildy. Tape SAT works with or without compression it does not depend on that.
 
It is very cool and your tracks will sound better for it. The EQ's and dynaimcs are very smooth and nice sounding inside Mixbus. You can then export your final mix from there and master in a later session. I also have the mastering EQ and Multiband comp and they both work very very well and also sound great too.
 
Mixbus can be used for just mastering a stereo stem too of a whole mix. It still sounds great even doing that. It is easier and faster to mix inside Mixbus than anything. You will see why once you get inside it and start using it. I like it too because it is all set up for K system metering and the ref level has been set at a fixed K-14 which is what I work at a lot of the time so that is great for me.
 
It is very much like taking your session to a hardware based studio with a Harrison console and that cannot be bad in any terms. It gets you out of your DAW for the mix which is also healthy and lets you focus on just the mix and nothing else. It is way fast and fun to use.

I like the idea of doing the whole mix in it, but one of the things that worries me is that it's 32 bit. Some of my favorite go-to plugs are Waves, and there seems to be a lot of problems related to having both the 32 bit and 64 bit versions visible. I haven't really worked all that out yet, but the upshot is that I got rid of the 32 bit Waves shell on the advice of Waves themselves, and I'm wondering what I'd be risking by reintroducing the 32 bit ones for the sake of Mixbus. 
 
Maybe I will try importing a whole mix stem into it though to get a ballpark idea of how it sounds. 

I like the idea of doing the whole mix in it, but one of the things that worries me is that it's 32 bit. Some of my favorite go-to plugs are Waves, and there seems to be a lot of problems related to having both the 32 bit and 64 bit versions visible. I haven't really worked all that out yet, but the upshot is that I got rid of the 32 bit Waves shell on the advice of Waves themselves, and I'm wondering what I'd be risking by reintroducing the 32 bit ones for the sake of Mixbus. 
 
Maybe I will try importing a whole mix stem into it though to get a ballpark idea of how it sounds. 

I like the idea of doing the whole mix in it, but one of the things that worries me is that it's 32 bit. Some of my favorite go-to plugs are Waves, and there seems to be a lot of problems related to having both the 32 bit and 64 bit versions visible. I haven't really worked all that out yet, but the upshot is that I got rid of the 32 bit Waves shell on the advice of Waves themselves, and I'm wondering what I'd be risking by reintroducing the 32 bit ones for the sake of Mixbus. 
 
Maybe I will try importing a whole mix stem into it though to get a ballpark idea of how it sounds. 

Well, the new forum software seems to be working out well. 

OK Sharke here is what you do. I did explain it above. You only use your Waves plugins and things within your DAW. However leave any broad brush stroke EQ for Mixbus. ie EQ that is not surgical in any way or EQ that is not a special tone shaping thing. Also you don't need dynamics on tracks or buses either unless they too are special in their effect. But for general compression and things you can also leave that for Mixbus.
 
You export now mainly buses but any tracks you might feel that may benefit from Mixbus. You export to a 24 bit file. This includes reverb returns as well. You should be able to export just the reverb returns of one or multiple reverbs. You import those as well and just treat them like tracks. You have to have everything right before any exporting.
 
Now you just use Mixbus and do not use any plugins at all now. Just use the really nice built in track and buss EQ's and dynamics. Basically you are just bringing everything together inside Mixbus. And adding any tape saturation as required too. Then you can still export a final 24 bit file of everything.
 
I am mastering inside Mixbus too but you need their mastering EQ and multiband compressor (which are excellent) and a limiter of choice. (In my case I use PSP Xenon)
 
Treat mixbus as if you are taking your tracks and stems to a room with a real Harrison console inside. You cannot use Waves plugins there either. You will just be summing applying some tasty EQ and dynamics before printing the final thing in stereo. And it sounds better than most DAW's! Don't let anyone tell you that 32 bit is inferior. A file generated on Mixbus even at 32 bit is probably going to sound much better than files created on other 64 bit systems.