Are MRA's the best way for a player to learn? I would say no.
MRA's generally care about 2 things, their numbers and the leadership, as long as the leadership and their mates can grow thats all they really care about. Theres very little learning goes on in MRA's, very often the leaders are inexperienced themselves and the general players in the alliance are just left to muddle along. Because most MRA's recruitment process is non-existent, with no expectations, the quality of players can be poor, and training and experience they get minimal.
Read a review of the grepo app on play store once..
got this game, build my city and joined an alliance, then they kicked me out and took my city cos i wasnt posting on a forum.. where is even the forum?"
which somes it up really. player recruited with no notice of experience, whether he was just using phone ap, no training given, eaten.. thats mra's for ya.
If you want to learn the game, join a small to medium alliance with some experience where the leaders are willing to teach and develop you (as long as you are willing to listen)
(of course there are some mra's that develop and teach, but they are few and far between)