The DLC is worth playing if you are near the end of the main campaign, if only for the +5 level cap which provides incentive for running more quests. Even though the DLC suggests level 20 as you are about to enter it, I would highly recommend level 30, as it is bullshit hard. I'm playing it on Normal and Hardcore and I'm about to tone down the difficulty after ]my first engagement with a pack of those fucking things absolutely destroyed me. As always the writing and plot is the best part about the content - some of the "twists" they drop on you in terms of gameplay are downright annoying.
I never really got into it, played the SNES version and got my shit handed to me multiple times. FF:T was such a cleaner, cooler experience, in general. The Ogre Battle Tactics whatever game (PS? PSP?) that was released was an abomination of entertainment. I wouldn't wipe my ass with the packaging.