A very good shave especially for the price
Some of this is going to depend on your beard. Even though I do not have a heavy beard it can be rather course. I am just about through a 100 sharks. For me the razor blade gives a very good shave (I usually do two passes in the morning) for approximately the first two or three days. Generally after that I believe it is not quite as sharp. I think the Merkur blade gives a better shave and will last approximately 5 days; however, due to the sharks being one-third of the price it is worth while to go with the Sharks over Merkur (I still use Merkur at various times) even if I change the blade every two days. Both are very good deals over cartridges.
Sharpness and Smoothness - Great Performers
Take a moment to view NICK SHAVES on YouTube and his shaving review of the Shark Super Chrome blades. His conclusion as well as mine is that this blade finishes strong and by the second and third pass this blade comes alive and provides a super smooth and close shave with nearly no irritation! I also like the Shark Super Stainlesss -- perhaps a slightly sharper blade but both are smooth, buy both and compare, you won't be disappointed!