I've ordered three times from Divervision and once from Fun-In-Underwater. Service has always been prompt and they've taken care of customs and shipping. Shipping is reasonable, usually about $20 for service in about 3-6 days from Taipei to my house on the west coast. Shipping was less, about $12.00 for a smaller item. I always get what I ordered and I've never had a problem. Generally, the service has been as fast and the shipping nearly as reasonable as I get from US suppliers. Many items are substantially more expensive from Divervision, particularly American made products like Light and Motion. Quality of the Chinese made brands they sell exclusively is decent, but not fabulous and the price is great. I recently bought a Nexus to Sea & Sea Adapter that cost me $140 plus freight and came in 4 days. The only alternative was a Japanese Athena model from US suppliers at over double the price. The quality of the part is excellent, though it came with no instructions. (It did include a Sea & Sea o-ring and a Nexus O-ring) It took me a little fiddling to figure out that the locating mark had to go on the bottom instead of the top, but otherwise no complaints. I bought a couple of 10" double ball strobe arms and lower ball adapter (aluminum rod type)from Fun-In at a total cost of $66 including shipping, to complement a set of used TLC upper arms I picked up on E-Bay. I haven't seen them yet, but I expect they will be adequate and I've been spending so much on camera stuff lately I didn't feel like spending $500 for a set of Ultralights. The whole thing cost well under half of that.
I prefer to buy locally, and I spend plenty at Backscatter on my weekly trips to Monterey, but I have no problem buying from anyone who gives me good service. No need to boycott anyone, if you don't want to buy from them don't, but they have some products that are unique, and I haven't found anywhere elsewhere. When exchange rates were better, they sometimes were 30% cheaper on Japanese housings. I came quite close to buying mine there.
---------- Post added March 4th, 2013 at 11:08 PM ----------
I just got the F.I.T. 10" double ball arms and ball mount bases ($17 each plus shipping) and they're quite decent. The 5x12 allen screws they supplied with the bases weren't long enough to go through the Sea & Sea lanyard adapters and have enough thread, costing me a trip to Orchard Supply -only black oxide metric allens, damn- but otherwise everything works nicely. We'll see how they hold up in use but at one half to one third the price of similar products elsewhere it was hard to pass up.