... besides price?
I've got a Gilette Fusion Pro Glide Homotopic Mapping Triceratops Hegemonic 5-Bladed Razor*. The cartridges for it are expensive, something like $4-5 or so a pop. Recently, I also bought a bag of cheap, disposable 2-bladed razors to do a comparison. Here's my take so far.
First off, the whole reason we men shave is so that daddy can get some sugar. We want to be smooth and soft, not raspy and scratchy. However, we shave in the morning, not at night, so by the time the smoothness is required, the beard has partially grown back. No matter which razor we use, there's going to be a little stubble. From my experience, a new, 5-bladed razor gives a slightly better shave, so by 9 PM, the stubble is a 1.3 on the Wife Owie Scale instead of the 1.8 with a new, 2-bladed one.
Shaving hurts when the blades get dull. More accurately, it hurts when the front blade gets dull. The thing then pulls on the whiskers instead of slicing them off cleanly like Robespierre on a good day. The front blade has no idea how many blades are behind it. Therefore, the front blades in both the Super Atomic Storm Chaser 5-Blade Razor will dull just as fast as the ones in the Goodwill Thrift Store Bargain Bin 2-Blade Razor. No difference there.
If the front blade's dull, the razors don't give nearly as close a shave. For one thing, you stop shaving sooner, leaving some stubble behind because you're tired of getting your whiskers yanked. However, because the Superstar Pro Glide 5-Blade Razor cartridges cost and arm and a leg, you'll let the dull ones go a few days longer than you will the Homeless Harry 2-Bladed ones. At that point, the 2-bladed razor gives a better shave than the 5-bladed ones.
Conclusion: 2-bladed razors are better. They cost less, give almost the same shave when both are new and will be replaced sooner than the more expensive 5-bladed ones.
* - Well, I think it's called something like that. The name's really impressive and it's got 5 blades.