I've done 3,600 miles in 2 nearly months 67% electric the rest on REX (obviously). BUY! BUY! BUY! Yummy. This is the car you are looking for.
My first day was 150 miles. And every day I'm commuting 120. Have done a 160 mile trip to visit friend with no charging. I am in the UK - so we get to use up the fuel first if we want. I keep about 25% battery if on a long trip so you can do some "overtaking" for a few miles, let the battery run below the set point and then slow down to let the REX catch up with the set point. TBH - you'll usually hit traffic that does that anyway.
I have learned where to knock the REX off on my way home - to the point it annoyingly kicks in about 100 yards from home sometimes (despite having 6.5% battery and the sat nav knowing I'm 0.1 miles from destination) and then still insists on doing it's cool down cycle (runs a radiator fan somewhere under the car).
Noise wise - you do hear it, and it reminds you of how your wallet is being emptied faster than stopping to put more electricity in
But it's not intrusive, sound like there's someone riding a nice quiet BMW 650cc scooter about 20 yards behind you (not one of the noisy 50cc wasps). I must go for a ride in my Diesel X-Trail just to remind myself of what noisy is! It's been sat on the drive for 2 months poor thing! The revs pick up as you go faster, it stops at 10mph and starts up again at 20mph. Unless you have really low SOC when it will embarrasingly keep running, destroying the portrayal that you are saving the planet and tippy toing around using nothing but wind and sun power and fairy dust.
Funny isn't it - you'd never ask someone if you can hear the engine in a 1.6 Jetta - because they'd say - er, what? Like of course you can - its' an engine, what did you expect? And that's the thing, don;t agonise over using it, think like I do - if I didn't have that little motor, I'd have to wait another 3 years to get an EV when the Telsa 3 comes out as I can't be doing with hoping the rapids aren't broken/occupied and getting annoyed with public chargers getting ICEd. I'm at the point where I'm going to sell the X-Trail and drive a 1000 mile trip to France in the summer. I'm confident that as long as I stop of regularly for fuel - and pick campsites with electric hook up then it will be just like driving a regular car. the best bit of course being that at weekend I often do 200 miles - but not all at once and all on electric.
As an experiment - I'm seeign how long my fuel tank lasts. Filled up 3 weeks ago, and still have 2/3. 490 miles done so far :-0. That's more to do with me giving up on the 120 miles a day commute, driving in 1 day, and using the train in between. Means I can use a public charger without much disruption to my schedule and more importantly as good as the ACC is in the i3 traffic assist, you can't yet sleep! The train solves that last bit.