Sonoma Coma

I was wondering what is better. I was going to purchase a nice simple 10" single bevel compound miter saw, a DeWalt DW713 for $219.00. Then I saw the DeWalt DW715 on sale for the same price. It is a simple 12" single bevel miter saw. They are both Direct-Drive motors. The 10" DW713 spins at 5,000 RPM. The 12" DW715 spins at 4,000 RPM. Then I saw a Double-Bevel miter saw, it is the DW716, a 12" Belt-Driven Double-Bevel that spins at 3,800 RPM. But is is $130.00 more than both the 10" & 12" direct-drive single bevel miter saws. Now does a Direct-Drive Motor produce more wobble than a Belt-Drive? Will the faster 1000 RPM of a Direct-Drive produce a smoother cut? The difference in RPM's between the Direct-Drive 10" DW713 and the Belt-Driven 12" DW716 is 1,400 RPM. Which will produce a smoother cut, a 10" or 12" blade? Is there really a need for a Double Bevel? I've read that alot of people say that it is not necessary. And the Double Bevel Belt-Driven 12" DW716 would cost $130.00 more than the Single Bevel Direct Drive 12" DW715. And what about the belt-drive system, I know that more moving parts will be more stuff to wear out, more things to replace, more potential for things to go wrong. What would you do...?