All the VV devices have ruined plain single-cell mods for me..... I don't use a regular 3.7v device with even LR attys, I'm spoiled by regulated voltage throughout the charge of the battery. The twist is a great device, just not long enough battery life for some- for me (I have the medium size mAh ones) its good. The newest version lavatubes have a higher amp limit supposedly. I have an original lavatube, and its a good device, long batt life with the AW 18650, but if I use dual coils (rarely) if you set it to a voltage higher than it can supply, it just knocks it down to what it can do. If you don't really use dual coils, and just want a bigger battery, lavatube is ok. It also gives you a little more adjustment for voltage- 3-6v instead of 3.2-4.8v. I don't know what LTs go for these days, but the smok tech vmax seems to have a lot of fans, and at $90(I think), might be a good choice.