Best i've used to longevity are DeWalt. I tend to use Black & Decker Piranha at work, because the place down the road sells them. They're pretty good too. With my DeWalt DW303K they cut through a 50gal oil drum like it's made of cardboard.
Never tried them. I'm particular to Lenox and Milwaukee Torch blades... but I wouldn't mind trying these out if you decide that you like them well enough.
If I remember correctly, theyre made by Morse, which are sold right next to the Masterforce blades. Im not sure why theyre cheaper, but im 98% sure theyre the same company.
I will echo the above comment regarding the DeWalt blades. I have tried them all, including the Torch, and I have had the most success out of the DeWalts by a sizable margin.