You have to narrow it down some. Are you shooting only 5.56, or do you want to suppress something bigger? How many rounds per year do you want to shoot through it? Are you mounting it on a CAR-15 or a HB target gun? Are you willing to $$$ for titanium? There are lots of factors that go into choosing a suppressor and I've only touched on a few.
NRA Endowment & DSC Lifer