I've bought from the five times now and they are far and away the price leader especially with that 15% off right now. On all of my orders I've ordered quite a few things and they always have shipped them out in a timely fashion. If they don't have a certain part they ship the rest and then ship the parts out that didn't ship once they arrive. Only once did I have to cancel a back ordered item and customer service is far from top notch but it wasn't bad enough that I've vowed to never order from them again.
In fact I just placed an order with them last week. I ordered an EOTech XPS, a Blackwater suppressor pouch and six of the new style Magpul pmags. With 15% off the final tally was good enough to put a smile on my face. They shipped the EOTech and the pouch but the mags were on backorder. EOTech and pouch arrived quickly and have been here for over a week now and my mags shipped yesterday and are due here Monday.
So, while I've heard lots of negative things about them my experience has been fine... borderline great really. Price is primary concern for me so when that's considered I would even say great. Some would rather pay more to be 'sure' but I paid under $400 for a brand new EOTech XPS which is about $70 less than everyone else. I paid $7.50 for a suppressor pouch that was $25 everywhere else and the windowed pmags were running about $13 each or so after the discount. Shipping was a little steep at $15 but that extra $10 or so spread over two shipments and all the items I bought is only an extra buck per item.