This all depends on the style of cooking you do. If you cook mostly from scratch and saute a lot of food on the stove top then the grease will accumulate. If you use an oven, microwave or steam oven for food most of your preparation then not as much. I can tell you from my personal experience that when I cook (mostly saute on the stove) I have oils accumulating on the hood and cabinets adjacent to the hood. This is true even with my 600CFM hood.
Cabinets door with mullions will be more difficult to clean as opposed to single panes of glass. Oils can also get behind the mullions.

All true from KBDesign. If you do heavy duty cooking grease/food particles will accumulate regardless of what you have. Glass does clean up though. Seeded glass will hide smudges or smears if you miss some when cleaning, versus a clear glass. I wouldn't let it stop you though, they are beautiful, a cleaner with vinegar will cut through the glass nicely. I think the best thing is to wipe down your cabinets regularly, sounds like a lot of work but a quick wipedown here and there will save you a big cleaning job down the road.

Thanks for all the advice. The clear glass cabinets are ordered! I'm definitely not a heavy duty cooker :) so I think the clear glass will work just fine. Again, thanks for the feedback!!!!!