So after trying numerous vv devices (ali'i, buzz, little sister) and other fixed voltage (glv 5v, big kazoo) I finally broke down and ordered a pro-vari with a 18650 endcap.  I have been satisfied with the other mods, but have found that they each have their flaws. 
I am hoping that the provari will be an upgrade. It seems that the provari is much more battery efficient compared to devices using linear regulators.
	
		
			
		
		
	
			
			I am hoping that the provari will be an upgrade. It seems that the provari is much more battery efficient compared to devices using linear regulators.