its sad that ppl still consider weight gainers good nutritional products. most of these products are made up of whey and sugar. now some companies are trying to prey on novices by not counting maltodextrin as a sugar because techincally its a complex carb something or other.
best way to increase calories is to slowly increase serving sizes a little at a time. that will work for awhile then you can look to liquid concoctions when the thought of shoveling more food in makes you sick.
only use those commercial products as a last resort after you have exhausted all other posssibilites.