I used the Mach 3 for a while, then the Shick Quattro, I just got the Gillette Fusion Power. Electric razors just never cut it for me, I've had 3 or 4 and they just don't shave close enough for me. No matter what razor I use I get shaving bumps so I've given up trying to find a razor that doesn't bother my skin.
I shave every other day unless I have something important to do. I used to change blades with every shave, but I realize how freaking expensive blades are and I squeeze about a month out of 'em. I think I get that long out of 'em because I first shave with an electric beard trimmer so there isn't much hair there when I get to it with the manual razor.
Now that I'm growing a goatee, I really like the stright blade on the edge of the Fusion it's great for shaping. Though how much can the improve a razor? Sooner or later we're going to be shaving with weedwackers if they keep adding blades.