cucaulay malkin:

I'm on mx-2 should I upgrade ?

If your application is old, yes. $6 USD a tube for something that actually comes close to the performance of the top stuff would be nice. MX-4 wasn't a galaxy away or anything, but there are pastes clearly above it, so if MX-5 is any real improvement at all, it should make those ridiculously priced pastes finally obsolete, with the exception of for those who want that sweet sweet 0.5C lower temp for 4-6x the price.