Sailorman,
you make some good points although I am still not sold that the lavatube is a better buy than the twist. I own and use(d) both although my LT is now put away. Let me lay out my reasons:
First, I think the kgo is a no go. I'd recommend a twist or a lavatube (LT) over it. I have a kgo and it's an awesome little vaping machine, but with the introduction of the twist and the LT, I think its a bit long in the tooth now.
second, the LT, is big. Really big. And heavy. The OP is coming from a Volt so It's gonna be quite a shock to go from that to a LT.
Third, I just think (and this is personal) that 2 650 mah twists are good enough. Yes, the LT is gonna give you longer vape time with is big battery but, it's not as though your never gonna have to charge it. I get just under 12 hrs on the LT per charge and I start to notice performance degradation before then. The twist is about 6 to 8 hrs depending on how you vape and voltage . Half the LT, I know, but it's a self contained unit, small, shirt pocketable and switching between 2 is not that much of a hassle. Also, even 6 hours is more than double what I suspect the OP is getting with the volt.
Fourth, I've never had a joyetech ego battery die on me yet. I know it will someday but it's not as though they die every 3 months. Also, LT batteries die too (and although I can't prove it, I'd assert more often than ego batteries) so I'd say it's a wash. Also, LT batteries are going to require a bulky charger. The twists chargers are equivelent to iPhone/iPod chargers. Plus, the twists can be charged via powered USB.
Fifth: basically the only difference between the LT and the twist is size and battery life. Both are Regulated VV, both are protected. Really it ends up being personal preference on size and form factor. For me, the twist is more than good enough. I know folks who put away their LTs and provari's (!) once they got the twists.
Of course, YMMV, but I stand by my recommendation.