I curently have a dean vendetta xm and am thinking about getting a new better guitar, but have a few questions what does 25.5 Scale mean and what is the difference between normal and jumbo frets.

Oh and by the way right now money is on ESP m-100 fm, is this a good choice.

25.5 is the length of the neck, in inches. jumbo frets just make it easier to fret a note. they need less pressure to sound a note, so you can play faster and more comfortably.

Not an expert on ESP's, so cant help with that.