Omega said
Cool, so I take it you would prefer Pathfinder then and the 2nd campaign?
Well, you said that the second idea could work with Pathfinder or 3.5. Pathfinder allows you to build any monster you want, which is nice--since they don't have as many books as 3.5. The race builder also allows you to create levels where you gain a monster ability periodically with your class features. Pathfinder might be the better system for the type of campaign you're thinking of.
Anywho. I'd be fine with both systems. I have all the 3.5 books. :D And there are a few monsters I've been craving to play, but the CRs are so high that I'd be leveling as a monster with one or two hit dice for 5 levels. :( I end up being very squishy with some nifty abilities, which works sometimes but not always. I always play a monster when I can. And either of these campaigns will allow me to do so. ^^ I will be happy with whichever system you choose to run.
Likewise, if you just want to compare systems, I'd be happy to discuss with you. I have played a looooooot of different systems. :) I love my tabletop games. My tabletop games just are always on hold during the summer, because my gaming group does things during the summer. Shock. Lol. I'm here to feed my roleplay addiction.