After my initial cig-a-like penstyle battery purchase, I read a lot of threads and it seemed the Vision Spinner was preferred over the eGo Twist. (This may be wrong, just based on the threads I read). So, I decided to buy the Spinner, a 1300 mAh one, and have been happy with it. The thing is you want a battery life that lasts more than 2 hours, as they can take anywhere from 2-6 hours to recharge, depending on the battery and charger, and you want a backup, and likely not *a* backup, but several. So, finding a kit with more than 1 battery is a good idea. If you don't get a kit, at least buy more than one so that while one is charging, you can use the other one. The ones that come with the tanks to put your juice in are even better, IMHO, to get you started on a more satisfying experience. The good thing about the kits also is they usually come with a charger as well. So, you essentially have everything you need to start. The reasons the Spinner seemed better to others (and to me) included the dial being marked so you aren't guessing what setting it is on (the Twist is adjustable also, but is not marked), and longer life. I would recommend at least a 1000 mAh battery unless you are a light smoker/vaper. I am in the heavy vaper category and my Spinner lasts about 7-8 hours, so not a full day. But, with either battery, you can upgrade to different tops that hold the juice, and experiment with different juice flavors.
Good luck to you on your purchase, whatever you decide to go with.
Good luck to you on your purchase, whatever you decide to go with.