The Gillette Fusion razor blades shave 5 perfectly. I do not know if having 5 blades rather than 3 is really significant, but somehow we hardly ever think it at Gillette, and the price has not increased significantly.
I found the Fusion blades more durable than Mach 3: 1 when I shave every two days, I can keep the same blade nearly 2 months without actually having to cut quality loss.
With the purchase of a pack, it's always a little wrong. But ultimately, with this pack of 12 blades less than 40, it has at least 1 shaving year (at the rate of wear is mine anyway), with just over 3 per blade.
I am fully satisfied with the XL pack Gillette Fusion, both for the quality of shaving and time / money.