Form factors are very similar and, on paper, they offer similar functions and performance. From the MI Witness site, the MV has been produced to the design of a company called TTW (Partners) Ltd, who happen to be the authorised UK main seller for Blackvue so it's almost certainly the case that the BV and MW are made by the same Korean manufacturer.
- MI Witness has two SDs cards. The smaller 16GB card is used as a repository for event files i.e. any events captured on the larger, second SD, are transferred to the smaller card to ensure that these are not overwritten by continuous recording - a useful feature.
- The MV has built in smart power (timer and volt) - handy feature if you wanted to hardwire, since you don't have to have a separate unit e,g. magic pro. That said, BMWs tend to have an issue with hardwiring, in that it will bring up a battery discharge warning on the i-drive. Plus, depending on your car's warranty status, you may want to power using a dedicated battery (when ignition off).
- The MW records braking, acceleration, G-force - not sure I'd want these, since hard to say whether having this info would go for or against you when using the footage as evidence.
- The GPS module is in-built on the BV whereas it's a separate module on the MW. This means that the MW front cam is about 20mm shorter than the BV, though they are similar width. That's a plus if you didn't want GPS but probably a negative if you did.
- Apparently, the MW has a reversing camera option (requires special cable). I'm guessing the images are fed through to your phone, so you'd have to always have your phone on view on the dash.
- MW has a 3yr guarantee.
- MW has a polarizing cap to put over the lens.
The BV and MW have different processors and different CMOS lenses. Other than noting that the CMOS is 2.4M pixels for the former and 2.0M for the latter, I have no idea over which is the better set-up. They both have similar fps (frame per seconds) values. The one review I have seen for the MW didn't have great picture quality, but equally the BV quality, while acceptable, is not the best out there.
Regards radio interference, a good number of cameras seem to have this issue but it seems to depend on the car and the setup. I don't think I have a problem with my BV though I tend to listen to the main stations and which would have strong signals. And chances are that as made by the same manufacturer then what affectS the BV affects the MW.
The one concern I would have with the MW is that the availability of any fixes and updates could take second fiddle to any fixes and updates that the BV engineers are working on for the BV range, rather than the MW spin-off.
I think that on balance, if I were choosing between the two I'd be inclined to stick with the BV, although the DR650 2ch has been out a while now and I reckon there'll be an improved model in the not too distant.