I have an istick vvvw v3. and a mpv 2.0. I still love them but I only use them on my old protank 2. Id love to have an mvp v3 simply because batterylife, build in charger cable for other devices, firing button placement, goes up to 30 watts! I don't see anything wrong with it besides it's main competitor: the Istick50watt. It's about the same size, a bit smaller, Goes up to 50 watts, I believe it has a bigger battery(Correct me if I'm wrong), and it's more affordable.
Kinda hard for any other box mod to compete with the istick 30watt/50watt. There are only 2 things I'd change about the isticks: I want easily replicable 18650 batteries to be compatible with them, Dc-dc current instead of pwm.
The mvp 3.0 is still a good device though. It has a built in device charger to help stand out against other devices, and it's build quality is superb. Not a bad choice if you ask me.