I used to use the Gilette Mach 3, when it first came out.  It was the first triple-blade razor and provided a closer, more comfortable shave.  Then I upgraded to the Mach 3 Turbo, which is supposed to provide an even more comfortable shave over the Mach 3 because it has those soft protection strips on both sides.  Then the Schick Quattro came out and I bought that...really great razor, shaves even closer with less resistance and is very comfortable.  It's only really mean on my mustache area, so I use the good old Mach 3 Turbo for that part of my face whenever I shave.
I really hope Gilette comes out with a Mach 4 or something (basically a 4-blade razor).  This M3 Power thing seems kinda stupid.