I just beat the 2nd Barthandelus, and i must say, that boss was hard. The game really does get more difficult towards the end i find, though if you really put some thought into your party and paradigms, you can fare okay. I enjoy having both a saboteur and a synergist out - you can just rape once your buffs and whatnot are up.
As for the first final fantasy game i'll be completing ever, it's pretty fantastic. I'm almost motivated enough to play through my copies of 7 and 8 and actually complete them this time.