I have an SI Defense lower(by accident,supplier shipped wrong one) and couldn't be happier with it. Assembled with no issues, fit and finish is very good. Color almost matched Mega Machine upper. Got about 800 rds. on it so far with no problems and it is a tack driver. If I hadn't just bought 3 Spike's "blem" lowers for 65.00 each at last gun show I would definitely order some of these.