Front Mission is turn based. AC isn’t?
It's 100% action, but it's very deliberate action.
The game is built, largely, around how you build your mech. There are, IIRC, several thousand parts that you can equip your mech with, with strict requirements for weight, power consumption, movement style, DPS, melee vs. projectile, type of projectile, on and on. There are plenty of story missions but there's also usually a one-on-one combat league built into the storyline that tends to have 50 or 100 opponents to fight.
They're generally very difficult, which probably isn't shocking coming from From.
I used to like them quite a lot, played the heck out of a few of them. Very similar to Dark Souls in that they're hard to get into but if you do you get sucked in good.