Among several others, I asked
http://www.leesails.com/ to quote for a new Genoa last year. They have a good reputation and their quote looked very good at first, but once I've added UK import tax & duty (using
http://www.dutycalculator.com/ - select "Sails - of synthetic fabric"), it came out slightly more expensive than the competing (UK based, although not all of them UK made) offers.
So for me, it wouldn't have been worth it, especially with the added risk of paying another round of very high shipping fees (US$ 277 one way) if there's any issues, plus hassles with bank transfers. But if your boat is somewhere with better import rates or you can arrange your own shipping from Hong Kong, it may be worth it for you.
Good UK based quotes I received were from Dolphin sails (Oyster suppliers), Hood (actually made by Kemp) and Sanders (whose Genoa I'm very pleased with). Elvstrøm could not compete on price and could not explain why the same spec sail would cost 35% more from them (I suspect this is because I made the mistake of asking through a local representative, which adds his profit).