ArM5 states that Magical Animal Companions (MAC's) should be 10 - size might. RoP:M expands on this considerably. The table lists low, medium, high, and legendary power levels, and for each, provides a suggested might for grog, companion, and magus level characters. The descriptive text suggests that grog level is appropriate for creatures that act as an extension of the PC with the flaw, and companion level is appropriate for creatures that are played by another player. Also, a magic creatures can have 100-1500 experience, depending on season and virtues/flaws.
What power and character level do you use for M.A.C.'s? What season do you use? Who creates the character, and who plays it?
Edit: I'm trying to let my players have fun and create potent characters (they are magi after all) without creating characters that steal the spotlight from other players or break the rules by turning a flaw into a major advantage by essentially doubling the magus' versatility.
It is a game where one player has summoning + commanding, and another has a fairie friend, so they've each got their own "entourage."
We all have munchkin tendencies but try to keep ourselves in check by staying focused on the story. This makes it harder for me to veto choices though; their munchkinism comes with plausible, interesting stories.
As we're still learning the rules, it can be hard for us to know when we are munchkins and when we are just using the rules effectively.
The player presented me with a magic raven of virtue, might 10-size, autumn season (720 xp). It has the gift, but no parma. He would like to control his companion as well as his magus. I think this essentially gives him 2-characters in one, making him more versatile and stealing spotlight. But the summoner can have any number of spirits, dragons, etc under his command...