I work at GNC. I mostly buy the Ultra Mega Gold w/o iron. Most of GNC's multivitamins are better than other brands I've tried, but they are expensive.
Personally, I like the Ultra Mega Green, but it does have about 10gm of iron. Yes, I know that men don't need extra iron, but most of the other minerals in UM Green are in dosages high enough to interfere with iron absorption. Supposedly they make one without iron, but I haven't seen it yet.
My least favorite was the Mega Men.
BTW, the Mega Men Sport is the biggest load of crap in the store (except maybe NO2). Lets take a male specific vitamin, and replace the saw palmetto with about a tenth of a gram of BCAA's. Ridiculous.