Both are awesome, but I bought a Mark 525. Mesa/Boogie staff treated me like gold when I visited their Petaluma facility in 1996 as a broke teenager. That is something that always stuck with me. Their amps are built like tanks. So far I have owned a Triaxis, Strategy 500, Simul 2:Ninety, Stowaway buffer, Mark 525, and Recto 1x12 cabinet. I still own all except the Strategy 500, which I only sold in desperate times after a car wreck and later replaces with the 2:Ninety. That being said, I later added a Revv G3 to use for when I want a different flavor. The Revv lineup is pretty solid and my impression of the company is that they are pretty down to earth and good to their customers too. Either one is a win.