As I can fully attest, every triad experience will be different.
Regarding conflicts...the 2 against 1 situation is inevitable. It's all in how you handle it. You definitely don't want anyone feeling bullied. But take a practical look into it. M has said that me and C don't agree on a lot, so if we both agree he has done something wrong, he believes it!
Also regarding conflicts...if you're mad at one partner, don't drag the other into it. Also, don't storm out of the house...the other partner will be just as hurt. (Maybe more so, since she didn't do anything wrong.)
Another piece of advice is work hard on communicating. If you head out and tell partner 1 you're making an errand run to the hardware store, don't forget to tell partner 2! Or, don't decide with one partner "Hey let's eat pizza tonight" and then totally leave out the other in the decision-making process. We've had that type of confusion a few times and it's a pain in the butt.
I've mentioned this article in another thread, but I absolutely love it. "Tips for Triads": http://sexgeek.wordpress.com/2010/03...ks-for-triads/
I've yet to find better advice than that one!