My experience with weight gainer products (and I've bought them all) has been this: Most are LOADED with sugar, carbs, fat and other stuff that you can do without. None provide the kind of "gain" you're looking for, which is muscle mass.
Only over the past few years have I found something that works for me - Lots of lifting, and a good whey protein supplement (like XXX or 100% Whey). They're cheaper, low fat and you won't get a sugar buzz... When you're training, you need 1g of protein for every pound of bodyweight daily... Hard to get that through a regular diet.
By the way, when I graduated HS I was 6'2", 135 lbs. Now i'm 6'1", 185, and in pretty much *perfect* health (for an "old" guy).
