The thing to look at with weight gainers is the sugar content. Extra calories are no good if it's all simple sugars. In NLarge2, there's 23 grams (or 90-or-so sugar calories), which means the powder is 1/6th sugar.
One of my best friends took NLarge2 and loved it. Said it was good taste and easy to take. Mixed well, too.
I'd go with real food first, but if you're really skinny, then a weight gainer like NLarge2 is OK. Most of the Latin American pitchers in the Chicago Cubs organization, who were really skinny but threw really hard, took a similar product at the recommendation of our strength and conditioning coach.