Yes it DOES make a difference! It's like having 25 lbs of pressure in your tires, instead of 32 lbs. You can roll on both, but one will give greater performance and economy.
Same goes with the base bevel. The flatter it is, the more it "bangs" on to the edge or catches the edge earlier. Too much base bevel, and the skis will have to be so far away from the body to make them hold, that you'll be out of balance.
The more dramatic the bevels, the more strength and finesse are required to control the ski.
I keep my normal skis at 1/2 and 3 degrees. This allows me any degree of performance I want, short of all out racing on very hard conditions. For my race skis, I run flat and 5 degrees, unless the snow is very soft. Some WC's get up to 8-9 degrees on the sides. Very sharp, but it doesn't last very long, and the ski has a finite life span.
For the average recreational skier, a 1 and 2 is a very good tune.