So far, I've made it to the tutorial mission that introduces Geo Effects and uhh....I can't see the colored tiles that mark a Geo Effect (turned every option on and off separately, nothing) which is a real bummer (Make note of the edit). Also wish they had implemented the speed boost stuff that Disgaea 3 onward used (holding down R1 or whatever during animations?), doesn't seem to be anywhere that I could see. There's also no way to change message speed, which is kinda ass as someone who's previously put 85 hours into this on the PS2 and just wants to skip it.
Edit: seems rebooting fixed it, though I'm running it in windowed mode now, maybe fullscreen has some additional issues at the moment.
However, I ran it fullscreen (with VSync on), and it holds a steady framerate...for the most part. turning on Shadows makes my framerate go from 57 to 37, every other option seems to not be having any adverse effect on performance so far.
For the record, my rig is an i5-4570, Radeon 270x, Win 7 Ultimate, 8GB Ram.