Well I've been using my twists since I picked them up on Tuesday non-stop, and the first battery just died. Both batteries had a full charge when they were received, verified by plugging them into the charger before any use.
What I purchased:
2 x eGo-C Twist (1000 mAh) batteries in White
4.75" (120 mm) long from tip to tip
9/16" (14mm) diameter (Same as a standard eGo)
They have the standard eGo cone threading, and white illuminated plastic push-button with 5-click on-off feature.
With a Stardust connected, the overall lenght is 7" (177 mm) which is much longer than I expected.
Build quality is outstanding. This device feels substantial and has a decent amount of weight to it. This battery would be very hard to damage from regular every day use, like all Joytech eGo batteries. The white coating is a soft-touch coating that a lot of manufacturers are starting to use these days and is pleasant to hold on to. The VV Twist ring on the bottom of the device moves smothly, but is stiff enough that it won't change settings on you if you leave it in your pocket. The numbers on the dial are very small. The only way I could see them getting around this would be to print the numbers on the bottom. This could be a hinderance to anyone with poor eye-sight, but it's really flavour and vapor that matter, the number is just a number.
The twist does exactly what it's supposed to do. You can turn the dial up or down to increase or decrease the output voltage. It ranges from 3.2v to 4.8v and using a multimeter both batteries measured out to that with in 0.01v. There are small indicators every 0.2V, but the range is completely smooth. You can set it half way between marks as there are no hard-stops except for at the ends allowing fine-tuning if required.
I found my sweet spot was at 4.0V on my LR Stardusts, and 4.2V on my SR Stardusts for flavour vaping GRBC's Rugged Blend. More than that and I either got dry hits, or the flavour changed. Lower than that and vapor performance started to drop. I also tried this out with my LR Cisco 308 I use for dripping a few different juices and it actually performed much better around 3.4v than it does on my standard eGo.
Well, seeing as I'm on 2 full days on the first battery, I can honestly say, the battery life is fantastic when vaping at between 4.0v and 4.2v. Pure vaping time, I would say is around 14-16 hours (I vape all day at work). Obviously YMMV if you vape with it at a different setting.
One thing I did notice is there was ZERO drop-off when reaching the end of the battery. I actually did a double take when it died because I had a perfect hit, then nothing. Regulated circuitry is a wonderful thing. I do wish there was some sort of battery life indicator on the device so you would know whether or not your walking out of your house with a near-dead battery.
As this is my first venture into a VV device, I can't compare to how well it performs against a Provari, or Darwin, but you can't argue with the cost. Batteries were $27.95 each from Canvape, so even with purchasing 2 I'm under 1/4 of the price of the other two devices after picking up chargers, batteries, etc etc to go along. It gives you an immediate option to change the intensity and flavour of your vape with very little investment. No funky menus to go through, or multiple buttons to push.
Would I recommend it? ABSOLUTELY. If this is your first trip into VV, or if you're looking for something smaller (Diameter) than a Provari or box mod for out and about, this product is an excellent investment. Extremely easy to use, good build quality, and good battery life. No complaints here.