This is about as big a scam as the cable "business" is. When I was getting ready to buy my LCD TV, I started getting parts and stuff I would need ahead of time, so I wouldn't have to buy it the day I got it, and possibly get ripped off.
I looked online, on Ebay and on several other sites, and noticed that several mounts appeared to be the same, with wildly varying prices. Some websites had the same pic for a cheap bracket, as another had for an expensive one.
So I went and looked at the local stores, and found the same thing, the same bracket was being sold under slightly different names, in sometimes the same colored box, sometimes the colors were reversed, but they were the same bracket. Prices ranged from about $90 to $299!
I ended up buying it on Ebay, for $45, including shipping. Same exact hunk of chinese steel, mine was silver powder coated, and the same bag of screws. As a friend found out recently, the lag screws that came with the name brand version ($149.95) of what appears to be the same bracket, are just as brittle as mine were. I snapped one off trying to screw it into one of my studs. I went to a local hardware store and bought 4 new ones for like a buck.
A friend of mine's dad recently bought a 46" Sharp LCD and had the store install it. They soaked him a lot of money to do it (His son and I offered to do it, but he never asked us), and used the same bracket I have, with the name changed slightly, and charged him $300! His son found the original lag screws in the box in the trash, so the brittle screws are a known problem.
Buy a cheap bracket, get some new screws and save some money for DVDs or something. Maybe a little bigger TV?