Anyone who's ever paid attention to FE9 will know how Mist vs Rhys debates plagued the community for years. When I first started debating FE9, I believed Rhys was better, but I quickly switched my opinion to Mist and to this day still hold to it. Regardless, the debate is pretty intense and I don't think I can fit even the major details in one post, so I'm going to simply focus on Mist's non-healing aspects and quickly compare them to Rhys.
Mist's advantages over Rhys include a much better support list, a horse post-promotion, and an easier time to get her combat up to par.
For the first advantage, Mist has one of the best support lists in the game, if not the best. She has very fast supports with Titania, Mordy, and Jill, with a moderate speed Boyd support, and all 4 are very good and likely to be fielded (There's Rolf but he sucks). The first three give full def, Mordy and Boyd give full att, Jill gives half avo, and she gets half att/def from the other combinations not mentioned. Rhys' list isn't nearly as good. Titania and Kieran only give half bonuses to def or avo, and since they have a lot more move than him they won't be in range very often. This leaves Mia who isn't very good and full att/hit doesn't solve any of Rhys' problems either. Ulki and especially Rolf are very bad. Supports give Mist a noticeable durability lead on Rhys when they're in effect.
The second advantage compounds with the first advantage. The horse has all the benefits of canto and such, which is very important for Mist because even after supports she isn't invincible (and her offense without the SS really sucks), and the horse lets her heal and get out of the way. The horse also means she can keep up with her supporters. Titania, Jill, and Mordy have 9 move, the first two having canto as well. Boyd has 7 move. 8 move and canto fits almost perfectly with these units. Rhys, getting no horse, is out of luck.
The third advantage is a bit more subtle and may not even apply depending on your playstyle, but it's there. Basically, to turn Mist into a usable combat unit, she needs either two arms scrolls, or an arms scroll + 10-15 attacks with steel sword, to be able to use the Sonic Sword. There's some competition for the arms scrolls but it isn't fierce, at least compared to what Rhys requires to close on Mist's statistical leads. Since he loses speed and durability and mobility to mist, he would need the corresponding stat boosters to catch up. That's a lot more resources to give him with much greater competition for them than what Mist wants.
Now Rhys does have some advantages on Mist, namely performance before Mist joins, as well as promoting before Mist. However, the latter advantage doesn't last particularly long as Mist can simply use physics for massive exp or even use a master seal (granted, so can Rhys, but the point is that Mist can promote shortly after Rhys). The first advantage is nice, but all it really tells us is that you should use Rhys for earlygame, then when Mist joins you should probably drop him for her. Unless you want to use both healers (which isn't a bad idea) or you really like Mia.
Bands: If you want to give the SS to Mist ASAP, give her a spd or def band. Otherwise str is your best bet.
Of course, being better than Rhys doesn't automatically make her incredible. Her durability is still bad compared to gods like Oscar and Jill, and it does take work to get her offense up. Healing is nice, but as said earlier it's a lot less necessary post-promotion which is where Mist actually has her advantages on Rhys. However, it's hard to pass up on that support list, and SS Mist has very good offense. Like, better than Boyd...
Edited by smash fanatic, 11 November 2011 - 12:52 AM.