I have an MVP2 and an istick. Not to toot my own horn, but I think my post will be very useful to you.
I used the MVP2 from July until about 2 weeks ago. I loved the battery life, the digital display, and the smoothness of the vape.
What I didn't like was the really stiff firing button, the fact that it wouldn't let me change voltages while it was charging, the size, and most of all, the darn firing pin! I use 4 different tanks with 4 different flavors on a daily basis. So my MVP went through a lot of screwing and unscrewing. After about a month, I started having firing pin issues, where the screen would read "NON" for no atomizer. I could fix it by pricking up the pin with a screwdriver, but I would have to do that every time I switched tanks, and eventually that wouldn't work either.
I eventually had to repair it with the oversized Danco #60 O-Ring. Now it fires fine, but the OHM reader is kind of all over the place now, and you can't screw it on all the way. This is a known and inherent problem with the MVP, not an isolated incident.
I've had my istick for about 2 weeks now. In terms of the form factor, I'm in love with it. Can't believe they could fit 2200mah in a device that's as tall as a BIC lighter. The vape is pretty good and it definitely gets the job done. It has pretty much all the features the MVP does, except for that recharging port that nobody uses.
What I don't like about it of course is the voltage issue. I actually vape at 3.8 volts, so the fact that the lowest it'll go is 4.0 (in real terms) bugs me. I also don't like that the voltage doesn't lock, so you can accidently change it in your pocket, or if you're holding it a certain way.
Also, the iStick gives me a rattlesnaking effect, where the signal isn't completely smooth at it's lowest voltage like the MVP does. I believe this is more apparent if you use single coil kanger heads like I do. People with Nautilus dual coil tanks don't seem to notice it.
Which one do I use? I still use both, but I don't use the MVP much anymore, and I never take it outside. It's too big and really is a burden in your pocket. I use the MVP at home from time to time when my batteries are charging.
To me, the MVP does give a smoother vape, but it's not enough to overcome the size difference. I think the rattlesnaking effect is more evident at lower voltages, so if you vape higher than 4 volts you might never notice it.
If I had to choose one, I would go with the iStick because of it's portability. If you're going to have a different vape for on the go, you might want to get the MVP but that kind of defeats the purpose of having such a big battery if you're keeping it at home, and be aware that it'll probably develop firing pin issues down the line.
I wouldn't recommend you buying the MVP2 at this time though. The new MVP3 is coming out by the end of the year, so you're buying something that's about to be antiquated. They may have fixed the firing pin issues on the new version.
Hope that helped.
P.S. The MVP isn't thattttt big as much as I seem to make it sound, but it is very big in comparison to the istick. Just like LCD TVs didn't look big and heavy compared to the old rear projection screens, but they're pretty thick compared to the new razor LEDs.
The MVP will still fit well in your hand. It's probably comparable size to a cell phone. Probably smaller.
