The quality of a print can make or ruin any design. In general, I recommend that you choose a local print shop that can provide you with a physical proof. A few print shops that I like are:
Radix Media (Brooklyn, NY)
Stumptown Printers (Portland, OR)
Brown Printing (Portland, OR)
Oregon Lithoprint (McMinnville, OR)
Helpful resources that I've found for folks who freelance and folks who hire freelancers.