Just to keep things in perspective:
At Hoosier, an 1100-mah kGo battery is $17.99 - cheaper than I thought.
KGO batteries 1100mAh
A 650 mah Twist battery is $24.99 at MyVaporStore.
A beginner with nothing is going to need two batteries and a charger, so we're pretty much talking about an extra $14 to have variable voltage. Yes, you will be swapping batteries more often with the Twist, no doubt about it. But you will be vaping with variable voltage as opposed to constant voltage. IMO the added cost and decreased battery life are well worth it. Others are certainly entitled to opinions to the contrary, although I'd be interested in hearing (in a dispassionate fashion) the reasoning behind those opinions.
Dispassionately speaking, one of the biggest complaints from new vapers, and one of the most common reasons for lapsing into cigarettes is battery swapping. People soon tire of constantly charging and swapping batteries. People don't want to have to carry multiple batteries in order to survive a day at work or a day out.
It is not fair to compare a 650mah device with a 1100mah device. Battery capacity is a MAJOR issue and not to be underestimated. All the variable voltage in the world is useless with a dead battery.
A fair comparison would be adjusted to account for battery capacity. Three 650mah Twists would be needed to almost equal a pair of 1100mah kGos. The full kGo kit is $44 for 2200mah. Three 650mah Twists, at 1950mah, are $75, plus charger, nearly 2X the cost of a kGo kit. A Vtube with 3200mah worth of batteries is $62 shipped. Even considering the VV factor, and in light of the long list of advantages the Vtube has over the Twists, the Vtube is less expensive and a better value than either the kGo or the Twist.
Two 650mah Twists would barely last you a day at work, and unless you recharged them in the meantime, you'll end up with nothing to vape when you get home while you try to catch up with charging. So, in order to survive a day away from a charger, you'd really need 3 650mah Twists.
As a backup or a spare battery, a $25 Twist is fine. But as a starter set, the price climbs rapidly and there are better options.