Patch 4.05 Machinist Rotation: To Overheat or Not to Overheat? Here are my findings.

[Leticro]

It ends up being 8 potency per overheat (net-wise). Over a 10 minute fight you'd do as much as a single auto attack.

The only reason to bother would be to sync up your cooldowns I suppose.

In my spreadsheet I got about a 400 potency gain per minute, so it'd save you a whole weaponskill or 2 (assuming 0% chance of procs), though that also means you somehow execute your skills perfectly of course, but that can be significant in savage because over a 10 minute fight, thats roughly an extra 30 sec or so of damage. (400 is roughly a GCD and an off-GCD average, and 2.5 sec per GCD)