They have some cheap and useful gear on the site, but their customer service is non existent. I have to file a paypal claim if anything is wrong and they will finally contact you. They commonly list items that are out of stock as "in stock" and will ship everything but that item without informing you. You pay higher shipping and they don't reimburse you for the amount. They don't even switch it for another item, but just remove it from their order and refund you.
They also lie about shipping items. If you complain to them, they will mark an item as shipped when they haven't even sent it out yet whatsoever. I'm still waiting and it's been two weeks and it hasn't shipped out. This is the LAST time I'm ever trying ACMgear.
Honestly if you have the patience and luck, order through them to save a bit, but in the end they are a pretty shit company overall.
Like Brian said though - don't buy BDUs or expensive gear from them - only the little nicknacks that don't matter as much. ACM stands for "All China Made" - and the quality is as you'd expect.