I'm sure you are going to get a load of answers telling you to look at specific brands, I certainly have my preferences that I have expressed by purchasing them. However, your needs might be different than mine, or anyone else's, so I usually ask people to consider what features are most valuable and which are not. That will allow you to pretty easily narrow down the hundreds of options to a few, making the choice much easier.
Here is a list, obviously not inclusive, that you might consider. Weight, durability, length, blowback, flash suppression, use with multiple calibers, POI shift, etc. Obviously you are probably just as, if not more, versed on cans than I am, so that is more a general comment for anyone who is reading. Here are a few things to consider with you purchase specifically.
How important is the ability to put your new 7.62 can on your existing 5.56 guns? It seems like you already have plans to get additional suppressors for those, so it might not be. If it is, then your choice is pretty easy, another SF in the 7.62 variety. Do you want the gun to be "KAC all the way?" If so, then the KAC is the necessary choice. If you are not married to either of those ideas, then the pool to choose from goes way up. If you want something lighter, I have been very impressed with both the Q and the Sig offerings as far as the tubeless with a larger diameter design. A friend of mine has a 7.62 sig can and it is incredibly quiet for the weight, although with Q essentially being the Sig cans 2.0, I'd just go with one of them. You can pick the 'QD' models with their muzzle devices, or the direct thread. If you are wanting a more traditional 1.5" diameter, I have been happy with my dead air Sandman cans, both the K and the S. They seem to do better with the bigger calibers (300 win was particularly good in the demos I've been to), and 7.62X51 works very well in the dead air stuff. Their mounting system is also very good in my opinion.
Once again their are so many options now, and many of them would be a great choice. Perhaps picking your highest priority feature and getting the can that excels in that might be a way to get something you'll really be happy with.