I got the album tracks to master in Mixbus 3 and I found they were in 48K. Mixbus had a terrible time just creating a session at 48K. It resisted with all its might!  After a lot of wrestling and crashes I managed to get it setup and playing correctly. You should not have to fight it so !
 
They dial in quite a lot of tape saturation as a default setting on the buses and the master so keep your eye on that and also they have a limiter switched on too. Once you pull the tape saturaton back and kill the limiter it all starts sounding a little more transient. You can soften things a little too much sometimes.
 
There is some stuff wrong with MB but I am positive and looking forward to it being rock solid. It is like any important update. It may contain a few bugs.
 
Have not checked midi yet or the included virtual instrument.

I have no problem with 48khz with my Presonus VSL44. I have read in a thread over at Harrison that people were having problems with certain interfaces.
I use ARC2 so I setup a template for it. "A tip"... at the bottom of the masterbus strip where it says post, click that until it says custom. Now in the fx bin you'll have "meter-Master" show up. Drag that up before ARC2 and your meters will remain accurate. The limiter needs to be off as it is last in the signal flow by default. Use a 3rd party limiter with ARC2.
The master bus fx bin should look like this.
 
EQ
COMP
Fader
"Limiter of choice"
Meter-master
ARC2

Thank you Clint very much. That is a cool feature. I am finding I am switching the order of the channel EQ around with a plug in EQ in mastering mode on tracks for example.
 
MB is well behaved once it settles down. Its like an excited dog wanting to go out for a walk but then settles into a steady pace.
 
I am going to have to do the limiting in another DAW for now so I can use Xenon.  But I am liking the sound of the mixer a lot and the multiband mastering EQ and compressor are really excellent for fine tuning things.  They sound stellar there is no doubt it.  That tune control on the masterbuss which just cleans up 200-300 Hz clug is great.
 
The EQ's on the tracks, buses and masterbuss are all a little different.  It is a marvelous mastering tool.
I am not using built in dynamics so much in this current mastering job.

I do have a few plugins that either won't scan or won't work at all, but most work just fine and to be honest I don't need much by the time I get to the Mixbus stage anyway. It's a great tool to have and the price is right. There are a lot of nice under the hood upgrades over Mixbus 2.5. I'm thrilled to be able to save projects on a different drive for example.

From the Harrison website:

• Experimental support for video timeline, video window, and audio+video exports

Experimental support? What does that mean?

I can't edit without Mixbus crashing. There are several bugs that need addressed to get this on par with Mixbus 2.5. I do believe it will be better in the long run, but it's going to take some time I'm afraid. The mixer view seems to work fine other than the plugins that won't work.

I was attempting to master an album in MB3 but have given up too. It is just too unstable and there is a little too much crashing and stuff going on. Too much time wasted rebooting etc..
 
I am back in SOP V3 and that is like a million times better. It too has had a major upgrade but at least we have also had a 3.01 update too which I think has addressed lots of things.
 
Maybe MB was pushed out the door a little early perhaps. It might take at least the first and perhaps second update to get it right.  Even MB2 is not totally crash free either. Yes it is better for sure but I can get it to fall over too without much effort.
 
I am real happy with Klanghelm MJUC right now and seems to be giving me the Mixbus sound without all the angst.

Yep, that is exactly what I was thinking. MJUC helps a ton getting that analog sound (love what it does for electric guitars that were recorded with a amp sim). I'm experimenting with Klanghelm's SDRR on buses and Sonar's tape sims...You can get there for sure, but I wish Mixbus 3 was ready now. I want to use it!!!

Jeff and Clint
I really appreciate your feedback on this. I am hopeful that Harrison will straighten things out, but I'm going to wait on them doing that.
Michael

Probably a wise move.