Geodude, congratulations on your 2017 REx!
I'm the original owner of an early-2014-build BEV that has had the following fixed under warranty:
– steering column loose
– A/C not cold
– driver's airbag recall
– climate-control panel flickering LEDs
– left motor mount cracked
– lower control arm cracked (this may have been from a debris impact)
– DCFC charging cable lock failed
– charging door popper failed
Most of these happened relatively early – the last four occurred just after the original warranty expired. BMW very generously covered most of it under goodwill which was greatly appreciated!
Since then it's been smooth sailing (knock on sustainably-sourced eucalyptus wood trim).
A friend with a 2014 REx (and later 2019 REx) had a number of "drivetrain errors" which ended in tows + long waits for parts from Germany. Those did come at the beginning of the respective ownership experiences, though.
BMW has been making the car for so long now – and there's just less to go wrong in an EV (though the REx does add some complexity) – that it's likely that your ownership experience should be uneventful at this point.
As skeptic mentioned, a dying 12V battery can strand you so this might be something to keep on hand in the next year or so – doing a search here for "AUX 18L" should bring up plenty of advice.
Enjoy the new ride!
edit:
Your original post asks "...how you feel about owning one" – to answer the question, I think the i3 is a brilliant design that's much more fun to drive than it should be and still is ahead of its time! I so wish BMW hadn't lost its way after the i-brand launch.
There's so much careful thought that went into making the i3 an ideal city car: short overhangs and insanely-tight turning radius for ease of parking, an ideal balance of commute distance vs. vehicle weight, a proper rethink of packaging that results in generous space for occupants in a small footprint.
I'm glad that BMW continues to make the i3 (I'll probably upgrade to the final model year whenever that is) but I must say that I'm disappointed that BMW i arrived here:
https://www.bmw.com/en/events/nextgen/reveal-bmw-ix.html