See, I like College OT. It gives both teams a chance to score plus it adds some drama especially if you hold the other team to a FG or shut them out completely. I realize that all the other team has to do in OT is stop them and they get a chance but it sucked to see the Vikes O on the sideline without a chance while the refs gave the Saints the W.
What I don't like about college overtime rules is that the second team to get the ball knows exactly what they need to win it. If the first offense did not score, they just need a FG. If the first team got a FG, they need a TD. That is a clear advantage in knowing what you need that the first team doesn't get. I also don't like the idea of second overtime or third overtime - let someone score and the game is over IMHO.
As for having a full extra quarter of overtime, I just don't see the advantage. It makes the game longer I guess, which is good or bad depening on whether or not you like long games. But it can still come down to whomever got the ball first if the two offenses are just ping-pong scoring back and forth and can still end up with no resolution forcing a second overtime. Personally, I think extending overtimes is dangerous because everyone's tired and it's that's much easier to get a significant injury.
It may not be perfect, but I like the current overtime rules better than any of the proposed alternatives.