hairball,
I don't have one with the built-in voltage display (yet), but Madvapes' description blurb states that the regulator is the Fairchild LDO linear, same chip/board used in their VV boxes without voltage displays.
I understand that your experience with the Madvapes VV Box was less-than-wonderful. I'd speculate that Madvapes lost quite few sales of the VV Box because your opinion is so well-respected here on ECF (for good reason). As you may know, my experience has been different from yours. I own seven Madvapes VV boxes and have never had any problems---no heat issues or melting/deformed plastic on the case, no breakage from drops, no malfunctions of any sort. Mine have all been monsters that hit harder than any other PVs I own (like you, I own lots---40 mods and 20 eGo clone batts).
Plus, I much prefer the linear regulator over the vari-cool/evercool switching regulator. Why? Because the Fairchild LDO handles (meaning, fires) any atty/carto you toss at it, whereas all the evercools seem to have an amp-limited cutoff built in (I'm not sure of that, since there are many different versions available now from the chipmakers, but I'm thinking ProVari, LavaTube, original Buzz/Infinity). But that's just me---most of the techies on the modder's forum much prefer the evercool, to the point of scorning linear regulators.
If you're interested, check out the 3AA box dual-14500 VV with an evercool regulator from Maximum Vapors. Least expensive evercool pre-built VV mod I know of ($45 shipped). Todd makes very clean builds and cares deeply about his customers' satisfaction.
Link: Maximum Vapors Ever Cool VV Box Mod
