Go with the CK Arms. The fit, finish, and quality of parts that CK puts in their guns is better. CK'S customers service can't be beat. I purchased their Thunder model in 38 sc 3 weeks ago, shot 1000 rounds through it. The Aftec would not hold adjustment. Sent it in on Monday and had it back on Thursday. I have owned a factory STI and their parts and fit are no where near CK'S.