Re:What do you shave with?
I used the Mach 3 for a long time. I recently switched to the Fusion, the 5 blade, and I hate to say it's better... but it is.
Regarding the Merkur, I learned to shave with one of those. I tried to go back, I bought one along with a pack of blades, and FOR ME it is not a solution; it doesn't shave as close, and it is not as safe, nor as quick, nor as comfortable, as the Mach 3. Let alone the Fusion.
Fusion blades are expensive, moreso than Mach 3 blades, and I could understand not making that switch just because of the cost. To each their own solution; vive la difference!