I had a salesman in Wanchai computer market last week desperately trying to get me to pick the cheaper Sigma flash unit over the Canon 580 Speedlite. I'd done my research and wanted the Canon....
Anyway, he opened the Canon at $3,200, which I was pretty happy with anyway, and then we got it down to $3,000... and then he introduced the Sigma equivalent, which I'd read about and didn't want, at $2,700. He then actually put the Canon under the table and started waxing on about the quality of the Sigma.... cut it to $2,500.... threw in a set of rechargeable AAs with charger... cut it to $2,390.... all the time, I'm saying, yeah, I want the Canon, and he's saying "they're the same! the same! save $600!"
They are clearly not the same.
But then, and this killed me, he took out his calculator and ADDED $21 to the price of the Canon! "EPS charge" he said. "No EPS charge for Sigma". Hahahaha. I never ever had an "EPS charge" at this shop before, what's going on la! What a load of BS!
Anyway I don't know if this Sigma fetishing was some kind of double bluff to keep me from negotiating hard on the Canon unit, or just cos the shop got a better margin on the Sigma stuff... either way, I left with what I wanted at less than list price and $400 less than Fortress, and around $19,000 less than Sogo, so whatever.