I just received my ProVari today!
Many thanks ProVape!
I'm really satisfied with it.
I seems like I don't even need LR attys in the future anymore.
A simple Joye510 atomizer with this device performs wonderfully! (on 4.5V)
It gives a much better throat hit than any LR510 attys before and it has a perfect taste (which I couldn't say in connection with LR attys).
Actually I don't know why would be important to use IMR high drain batteries for this device.

I'm using a cheap Chinese Trustfire 18650 battery for it (it's not high drain at all) and I've been vaping for about 10 hours almost non-stop (chain-vaping) and the battery is still almost totally full.
I guess it'll drain (based on these 10 hours) after about 2-3 days, so this is absolutely perfect, I can say.
If a battery lasts for more than a whole day on 4.5V... then I couldn't imagine anything better than that.
Of course it could last for weeks haha... but who cares? It's not a big problem to put the battery on the charger at the end of the day. (or at the end of the 3rd day)
The device is very well built, it's solid and looks good. The well on the top of the device is VERY useful against overdripping.
About the weight: It's not extremely heavy. Heavier than almost all the devices I tried so far, but it's still not too much.
By only problem is: the button stucks in, all the time. It's quite disturbing because I almost burnt down my atty with the very first button press.
I realized that if I push the button a little bit downward during the button push, then it doesn't stuck in.
So it's not a very big problem anymore.
Anybody else ever experienced this problem with the button?