Get a Omega boar or Omega S synthetic brush - not available on amazon, it's at maggard though. Those are cheaper than crappy badger, even, and far better. I started with a silvertip badger and don't even use it anymore since those ones are so good. I've got a cheap merkur DE and a couple of old straight razors, I find myself reaching for the straights more often than not. Haven't tried a shavette.
I used to do double edged safety razor for a few years, because the blades are so cheap, but I finally gave up because I got tired of nicking myself all the time. No matter how skilled I became or how much time I took to shave, it never stopped slicing up my face.
I have read that you either love or hate the vibrating handles, it definitely works for some people. It's possible you didn't get the right blades for the DE, though. If anybody here is going to try it out, get a blade sampler pack. Some blades will nick the shit out of you and nobody can tell you which ones will do it on your face. If you're getting 2 months out of a mach 3 blade, though, it sounds like you've pretty much maxed out the savings. That's only 30-some dollars a year in blades.