I have owned the 3 Benchmades you mentioned, and have sold all of them. I was initially taken by the 722, but found it not suiting my personal tastes. You might want to look at the Benchmade 730/735, I have owned just about every current production Benchmade, and aside from the AFCK series and balisongs, this is the only one I do/would carry. Don't get me wrong, the Benchmades you listed are nice knives, I just personally prefer the 730 model myself and got rid of the others due to personal preferance. I have been a big fan of Benchmade as long as I have been in knives, and have carried one or another with me almost every day for the last 5 years or so and have never experienced a failure with one.
Onto Emerson, I recieved a CQC7B waved a week or so ago and was initally very impressed, and so far still am. Well designed and well executed. I really, really like this knife

I also just got an Emerson SOCFK, very nicely designed, feels great in the hand, but the action basically sucks. I am going to give a few more tries to loosen it up, and if that don't work, I'm afraid I'll have to send it in for some work

Aside from the lack of smoothness, it is a nice little piece. I suggest you look into one of these, as it is quite similar to a Specwar, only with a wave

I have no comment on the Commander, other than I dislike the blade shape on it.
As far as QC issues go:
Emerson--The SOCFK is the only problem I personally have experienced... simply a tight action. But I only have a little experience with Emerson, so take it for what you will. I did email them on a seperate concern of mine on a knife I would like to purchase, and they were very nice at answering questions and fairly quick about it for email, so I doubt that service will be a problem.
Benchmade--Never have had a problem from them. Maybe an edge is a bit thick for my liking, or something like that, but with my experience in working as a QC/QA inspector for a while on things that cost a lot more than a Benchmade, this doesn't bother me at all as it is quite easily fixed at home. I have dealt with their service department as well as a few other people in their company, and they are absolutely wonderful. Never had a worry when I sent a knife in to be looked at or worked on or whatever.
Reading that it appears that I didn't make much of a choice one way or the other, but I hope the information is at least a little helpful.