My only issue is the only way to be sure of UPS shipping is do next day or air and its expensive that way. Couple of UPS stores I've had stuff delivered to before gave me a "we can't accept mail from USPS and this is the last time we will accept delivery".
Midway, which I haven't ordered mags from (well, not >10 round mags) and had delivered out of state UPS ground shipping is a regular option.
So with Gunmagwarehouse I've always put in "big" orders to make paying $25 in shipping worth while.
I didn't know about the UPS stuff. I just have them ship to my brother and we meet at Cabela's in DE for lunch and swap.