I haven't driven the Kia e-Niro or the MG ZS so can only go by what I've seen online and extrapolation from the two EV's I have owned, but I would say the MG ZS is probably the best value for money for the range you do get (but it will not do 200 miles - it's more like 150 miles) while the Kia e-Niro is probably the best value for money in the >250 mile range category as well as the most reliable EV in the >200 mile range category.
Perceived quality and image may be an issue - the MG ZS is as pointed out Chinese made and while it is a fairly good car when you read between the lines from owners on forums there are a few limitations and shortcuts taken with the design of the car, some of them a bit silly like simple features like charging timers etc... cheap, cheerful and decent is how I would describe it.
The Kia e-Niro probably has a "low perceived quality" in the eyes of anyone who has not kept pace with how rapidly Hyundai and Kia have improved their quality in the last 20 years, to the point where their build quality and reliability far exceeds that of the majority of European Marques including our beloved PSA and Renault. 20 years ago I would have looked down my nose at Kia and never bought one, and with good reason. But today I would gladly have an e-Niro for a family car.
The engineering of the EV drivetrain in the Hyundai's and Kia's is second to none - they achieve almost unbelievably high driving efficiency compared to all other EV's, the only thing that comes close is the latest 2020 version of the Tesla Model 3 which adds a heat pump. Prior to the addition of the heat pump the e-Niro still handily beat the Model 3 for efficiency, and they're now pretty much neck and neck.
To give you an idea just how much more efficient the e-Niro (and Tesla Model 3) are than some of the European competitors, Fully charged recently did a road trip with an e-Niro and an Audi e-Tron - on that same journey the e-Niro averaged 5 miles/kWh and the e-Tron averaged 2.5 miles/kWh! (On a similar journey I reckon I'd get around 3.8 miles/kWh in my Leaf - somewhere in the middle)
Ok so the e-Tron is one of the most inefficient EV's around but some others like the i-Pace are likewise very inefficient. Inefficiency means much less range for the same battery size and also increases charging time per mile travelled since you need to charge more to cover the same distance.
If you look at reviews for the e-Niro it is generally getting very positive reviews - not everyone likes the styling of the front end or finds the styling a bit "boring" but not one review I've seen has said anything like poor build quality, poor reliability etc... some reviews are after a year of ownership and are still very positive, and I have not heard of any showstopper design flaws or reliability issues with the e-Niro yet. (The Kona had the issue with battery fires - but the cells used in the e-Niro are not sourced from the same factories that had those cell manufacturing issues for the Kona so there has been no battery recall or spate of fires with the e-Niro)
I guess my point is we need to put aside any outdated preconceptions of perceived quality and image which might date back a couple of decades or more. On the engineering and build quality side in EV's in particular Hyundai and Kia are really nailing it in the last few years, and they are really gunning for Toyota when it comes to overall reliability. The fact that Kia are willing to give a 7 year full car warranty (which includes the high voltage system) shows that they have confidence in their reliability.
And the brand new EV platform that Hyundai recently announced (which Kia will share) looks very well thought out and forward looking.
One big difference between the e-Niro and MG ZS is that the MG ZS is a traditional estate / station wagon, which is very rare among EV's (it might even be the first estate EV!) while the e-Niro is technically a crossover SUV hatchback. However despite this it's not a "high" sitting crossover - I've parked my Leaf along side the e-Niro a couple of times and to my surprise it doesn't really sit any higher than the Leaf - either driving position or roofline so it's barely a crossover, I'd call it more a "high hatchback", like the Leaf.
Width and length is also about the same as the Leaf - which is also the same width and length as a Xantia, so it's not a big car as such. Not too big, not too small, and with a much flatter wider boot than the Leaf.