Hi matt and welcome to the VU!
Both those little guys are pretty new and not off the market...I haven't gotten a chance to play with either one but it's going down to the small details in what you want in a device....The MPV 3 has a huge 3800 mah lipo pack in it which means you can't change the battery but you're going to get a longer battery life than than the IPV mini running off a single 18650 IMR...the best battery life you're looking at for that is 2500 mah.
Also, as with previous MvP 's you'll be able to to use it as a portable power bank if you need a battery pack for your phone or something in a pinch. The rest is in the specs. The MPV has a wider voltage range of 3-9 volts but only has a resistance range of .4-2.4 ohms compared to the .5-3 ohms of the ipv. Then again, I don't really know anyone that uses a coil above 2.5 ohms anymore so that's not a big deal.
The MVP adjusts in .5 watt increments and I haven't been able to find what the IPV adjusts at but since it's a little YIHI chipset it's either going to be .5 or .1 but again,,,,jumping in half watt increments instead of .1 isn't really a big deal...I've never heard anyone say they have to vape at exactly "X.3" or "X.7" watts for a happy vape.
Innokin has always made solid regulated products, IPV also has done very well but their track record isn't as long and has a small blip or two on it.

My best advice to you or anyone is wait a couple weeks...yeah, I know waiting is hard to do but you have to look at it like this. The vape industry is so cutthroat and new things come out so fast that in two weeks all the reviews will be done, all the bugs will be known, and the price will drop probably 5 percent or so as the next "big thing" comes out and you can make a happy, informed decision while someone else worked out the bugs. With my luck, every time I bought something with in a few days of it coming out I always had one of the ones that came with issues.
If I had to choose one on the spot I would go Innokin because I have had nothing but good luck with them...I've never owned anything from IVP and am in no hurry to buy something from them. If your current vape can hold you out another week I would do that and make the informed choice. Sorry if I am no help, but I try. Best of luck to you with your choice....
and happy Vaping!
