In my own personal experience, I don't like how in FATEs all i can do us spam Miasma II and maybe Bio I a few times. Stuff just dies too quickly for my DoTs to be of any use.

As far as dungeons go, I feel pretty powerful. I like seeing my 700+ Fester criticals and my DoTs seem to do a decent amount of damage.

My only major gripe is the summons themselves. The single most annoying thing I have delt with was trying to ride my chocobo past a few hostile creeps only to have my Egi go out of its way to attack them. After moving about 20 yards or so they withdraw and then I have to resummon them when I dismount. People have told me to click on "Heel" before mounting up but that doesn't accomplish anything. Also, not being able to command your summon's movements while casting and recasting DoTs is a huge pain, especially when your Garuda is in the line of fire of a massive line attack. Then assuming your fast cast is on cooldown, you have to waste 4 or 5 seconds to resummon it.