Note: as far as I can tell, these folks are completely separate from HobbyAsia.com, which has been discussed before. If I'm wrong, or if this retailer has been mentioned before (yes, I searched) then please let me know.
Anyway, at the moment this particular vendor seems to be ebay only, although they've got a stub website at www.ehobbyasia.com.
I purchased a M1A1 Thompson from them, and have since ordered a MP5K PDW and G3 SG1 on behalf of friends. The first one I got through ebay, but since then I've just mailed them for price quotes, as they seem to stock far more than they have listed on ebay.
All three of the orders arrived within 3 days of payment, and I got order confirmation and tracking information immediately. Their prices are very good, and they've also sent free goodies along a couple of times. I also forgot to order rings for the SG/1 along with a top rail and scope, so they sent some for free. Their responses to queries of any sort have always been very prompt, extremely helpful and accomodating, and in very good English (they're HK-based.)
All in all, I've been extraordinarily pleased with them, and would order from them again (via ebay or otherwise) in a heartbeat.
I've ordered twice from them, my most recent purchase was a G&P Aimpoint - took over three weeks to get here from HK. I'm not a fan of the wait as I was expecting the item in time for a game on the 25th, but I guess they have good prices on their items...
I ordered my switch assembly from them and I got it in a week after they shipped it (which is ok), so I ordered a G&P aimpoint from them also which should be here this week. They do pretty good business as far as I can tell.