The benefits of an electric loader cetainly outweight the negatives. In fact I really can't think of any negatives.
Just think of how irritating it is when you have the perfect shot on someone you pull the trigger and *BANG* nothing comes out because you didn't shake your marker. Now your opponent turns to fire at you and you're toast because he knows you're there.
Not to mention the 12volt Revvy's are now only like $20 - $25
. Cheap as they have ever been. PM me for the site.