My understanding is that almost all major goods (i.e. TVs, white goods, etc) are sold in a "showroom" sort of model--Fortress, Broadway, the random Mongkok guys you find on Price.com.hk ALL sell goods straight from the manufacturers warehouses--not their own. If you buy a Samsung TV it is delivered from the Samsung factory warehouse by Samsung delivery people and installed by Samsung technicians and supported / warranty service by Samsung technical staff. It makes no difference if you buy it at Fortress or on the second floor of Golden Computer Centre from a bunch of guys playing video games--the back end is the same, but the price is considerably different.
I ran into this when buying a Samsung TV from Fortress only to discover it for about 30% cheaper from a guy in Sham Shui Po. When we looked at the inventory availabilty at both shops it was the same stock and the Fortress guy laid it out to me how the product would be delivered/installed/serviced. I've seen similar with a few other large purchase items.
Anyway, fwiw I used HDlife.com.hk for my TV. Was fine. I use Builtinpro.hk for my white goods.