Illusion of Gaia is probably my favorite Zelda-ish action-RPG that generation. Amazing game. SoulBlazer is also good, though not as great as Illusion of Gaia. I still haven't played Terranigma much, though, sadly... stupid Nintendo, for not bringing it out in the US!
As for Secret of Mana, I got that game as one of the earlier titles I got for the SNES after I got the system in '05 or '06, and was disappointed; it's super-grindey, and the game got boring. I lost interest partway through, grinding constantly is not fun, I want to just be able to play each area once instead of having to go back and forth grinding every time! I really dislike the long delay on your attacks, too, that long pause between a hit and the enemy's reaction to it. The combat suffers as a result.
Seiken Densetsu III is a much better game mechanically, it fixes Secret of Mana's faults. It's a fantastic game. I still like the first game, Final Fantasy Adventure, best, in the Mana series, but SDIII is second. The stupid long delay is fixed, the game flows better with a bit less mandatory grind (though hit's a Square game so of course it still has grinding), the story is a bit better, and more. Square really should have localized it... though Secret of Evermore actually is a good game too, and does play a bit better than Secret of Mana as far as combat goes, even if it's no match for SDIII.
Overall, though, I prefer the more Zelda-like play of FFL to the charge-attack-centric combat system of SoM, SDIII, and SoE. I just don't really care for that kind of wait-up-and-charge-attacks style of play -- I don't love the platformers The Legendary Axe or Astyanax, either, both of which have combat systems with a charge meter sort of like the one later seen in SoM. FFL does have super moves with a charge meter, but it's not as central to gameplay as it is in the SNES games. It's more about Zelda-like exploration and hack and slash action, though the game does have grinding and such at times as well, of course... it being a Square game, and all.
