As previously stated, do NOT go to a small shop for your suppressor. Sound suppression really is rocket science and the top tier of companies have invested heavily in the science of canceling sound. In this industry you definitely get what you pay for to a point. That being said I can't believe these's enough difference in a $800 can vs a $1500 can. I don't believe the human ear would ever tell the difference nor do I believe they'd meter much, if any, diferent.
My recommendation would be Liberty (and you can go shoot theirs before you buy. They're in Trenton GA), Silencerco or AAC. The Dead Air guys quit or were forced out of AAC after the Remington merger. They know the science and I would buy their product in a heartbeat. And I WOULD get the 30cal for dual use. There are 30cal cans on the market that are very close to dedicated 5.56 cans in suppression.
All that said, there's more smiles per outing with a rimfire can. It's cheap to shoot and leaves a huge grin every time.
I spent 2+ years researching before spending a penny. All you could ever want or need to know is right here.....
http://www.silencertalk.com/forum/index.php