I tried to make myself content w/ switching between 3.7v and 6v and failed repeatedly. That feel of a fresh battery at 4.2/4.1v was ideal and it really started making me notice the battery drop-off. Go w/ a Vv and keep a static all-mechanical as a backup w/ LR attys.
I have a ProVari and I'm fairly happy with it. There is no reason for me to replace it and I think one reason it's in the classys so much is because it's a reliable workhorse and people notice how much better they are so they also trick their minds into "upgrading". Part of the compulsive/addictive side of vaping. I don't think it's a negative reflection on the ProVari at all.
With that said, the ProVari is kinda sterile to me without being sexy. I have a few from the Precise line which is static, sterile, plain in terms of features, but it's solid and really bloody sexy. I can't think of a better or more pleasing fixed 3.7/6v mod. However, I'm replacing my ProVari with a Vv GRIP because I want something more unique. It won't have all the bells and whistles but it still beats the ProVari out in my gut. -Magnus