Yes, but there are better pastes, and thermal pads, on the market. HOWEVER, unless your going to delid, or use aggressive overclocking, the differences between pastes is around 1c difference in temps. So penny for penny, as long as you use name brand stuff and not the shit they send with the cooler, you'll probably be ok. If long term performance is a consideration, and you don't want to have to reapply every few years when it dries, you may want to look into pads.
I'm used to at least yearly disassembling and cleaning my computers, so a pad might just be more hassle. Also, I haven't used them for a processor before, only GPU memory chips. They're not the easiest thing to get right, at least for me.
MX-4 or MX-6 then. 6 is too thin, IMO, and I notice better peak heat management with 4. 6 works better with water cooling, or so I hear.
Didn't even know there was a 6 out. My tube of 4 lasted years. Thanks for the info.