I'm glad you like yours and that they work for you, but my experience was just the opposite.  I put them on a Cub Cadet zero turn mower with a 54" deck and they cut ok, but definitely not better than the factory blades.  They also took more power (in tall grass I had to go considerably slower than I had with the old blades) and I was disappointed in how long the blades lasted.  I use a different mower with a larger deck now, but I had switched back to an aftermarket blade on the Cub before I changed mowers.  Personally, I wouldn't recommend them...

Mike

Edit: I still have the centers and blades from my Cub if someone wanted to buy new knives and try them.