The i8 was woeful in comparison in all departments. They are different types of cars but the only area the i8 could speak up a little bit was in the looks department.
I haven't tried the i3 but I think it has a certain style of it's own. I'm not a huge fan but I like to see it when it rolls by as it means one more victory on the way to electric cars (and one less diesel cloud filling my lungs).
It's easily one of the most popular EVs here in the UK (along with the Tesla, Renault Zoe, and Nissan Leaf). Very nice to drive with a stylish, comfortable, minimalist, premium-quality interior. BMW's software does let it down, though - at least when compared to a Tesla.
But still, i'd argue if you want an EV and can't afford a Tesla, it's the best option available right now (at least until the Bolt is released).
The EPA range is fairly realistic in my experience, at least with a Tesla. Hills and climate control (AC not so much, but heating is huge) will affect it, but I get fairly close to the official numbers much of the time.
The NEDC test is much more gentle and provides wildly unrealistic numbers. You won't achieve NEDC numbers unless you're doing something like a steady 55MPH on level ground with no climate control.
You can see this in action by going to Tesla's design page and switching the country between the US and the UK. For the US, the Model S 60 is rated at 218 miles and the P100D is 315 miles. In the UK, those numbers are 253 and 381.
BMW says 300km, or 186 miles, for the larger i3 battery under the NEDC:
http://www.bmw.com/com/en/newvehicles/i/i3/2016/showroom/ran...
But the EPA range is more like 125 miles.
Tesla's stated Model 3 range of 215 miles is the EPA rating, and so should be fairly realistic in mild conditions, less so in the winter or with a heavy foot. The BMW number to compare to would be 125 miles.
I wouldn't compare anything to the model 3, though, because I don't believe teals will hit their dates or price point.
Not a BMW fan at all, default detest of that brand, but I respect their trying to push into e-vehicles. i8 was a big mis-step though. Cannot believe anyone bought it over a Tesla.
And, yes, it's a hassle. Life with a pure electric is simple: Plug in at work, plug in at home, plug in at the mall, visit superchargers during trips if needed.
With the BMW's you have extreme electric range anxiety (only 80 miles) if you want to "be electric" and you have to now: plug in at work, plug in at home, go to the gas station by work, go to the gas station by home, plug in at the mall, gas-up by the mall, no superchargers during longer trips, so gas-up frequently due to the 10 gallon (or is it 8?) tank.
Then there's the complexity. You are lugging around 2,000 parts you didn't really want to be lugging around. Is that generator built to last like real auto propulsion engines?
Put it simply: It's a pain in the ass, it is likely to require more maintenance and it is embarrassing.
(and yes, the gas engine in this kind of drivetrain will mate to the electric motors during power intensive operations for a boost, but that's not strictly required in this kind of approach)