I'm yet to use it. However I've done a lot of research into it, and spent some time thinking about it (materials science background finally worth something
)
It will be better than any paste, if used correctly. This means it must wet the surface, run into all the little cracks. This also means the little cracks cant have mx2 or as5 in them. Cleaning with isopropyl/acetone does not (and can not) remove all of the paste. If cleaned with ipa then used, it gives about the same temperatures as AS5 and people wonder why bother.
However, if you lap both surfaces to remove any trace of old paste, clean thoroughly to remove all copper dust, then apply the compound
as the instructions tell you to then the results are inevitably better. Its as close to solder as we can realistically get. If you fail to follow the instructions, and don't lap the contaminated surfaces, your results will be nothing special and you should have rtfm.
I will be using this. But for the above reason, not until I lap my processor and waterblock, and I'm not doing this until I've got the last pieces of my loop waiting to be installed.
Oh, it can glue stuff together, so mount it in such a way that you can twist the block to break the connection. Pulling straight up might not go well, in the case of the ek mounting hardware this means missing out four nuts.
Cheers
^Good to have you back Bulldog