Thats interesting, the m5i really are a great speaker and a compact size, I also find them a lot less fussy than the other epos like the es series, as in you can use them with a wider range of amps/sources/rooms/positions and they still sound good. But I would give the ultimate finesse to the larger es (and possibly 'm' models) given the right circumstances. But as you say the crossover is supposedly more complex with the 5s.
Not seen many reviews for the i's, I don't think they had as much of a run life as all the models that proceeded them.
one thing I would like to see is how the cabinet is made as they weigh a ton dont they. I hauled my pair in the original box back across London, 20kg, lol never again, I dont know how many times I stopped to get a breether... I understand they have some kind of shielding in them so they could be used with audiovisual equipment.