The eGo-Twist from Joyetech has been referred to as a "gamechanger" and I couldn't agree more. The eGo-Twist is, in short, everything a vaping device needs to be without being complicated or expensive.
The Gripper is a nice little 3.7v mod that offers a simple, compact vape for just $20.
The ProVari Mini has all the same features (the same control unit) as the ProVari V2. This means the Mini is the only unit of this size to have basically every feature and protection you could dream up. Overall, though the price is high, you will get exactly what you pay for here: the best of the best, in a compact size.
Overall, while the cartomizers have some issues with the size of the hole used, it's no knock against this product as a whole. The design is great, it doesn't leak at all and it allows you to vape for days without any dripping or any work. If you're looking for something to cut out the constant filling and re-filling, this is a great way to go for a very small investment.
The bottom line here is that if you're not that concerned about the looks of a product that will be large and a little unwieldy regardless, the price here to get a variable voltage or big battery mod is a steal.