I would highly recommend moog as an aftermarket supplier. However, after working at a dealership for almost a year and previously working at an independent for 4 years, I would highly recommend oem parts over aftermarket. I love not having any issues and knowing my parts are gunna last.
One thing, we do use a lot of ac delco instead of GM parts which are still better than many aftermarket parts. GM stands behind them, I figure, can't go wrong
-cheshire