Both Mass-Tech and Serious Mass seem to fall under the "standard weight gainer" category: maltodextrin as the main carb source, and whey as the main protein source. Mutant Mass, like kornholio pointed out, seems better. Another one that looks better is Up Your Mass.
http://www.bodybuilding.com/store/mhp/mass.html
One thing you might not like about Up Your Mass is that its main protein source is soy.