I decided on a '15 4hs, which I've had just over 2 weeks. I do occasional long journeys (this weekend it was Basingstoke to York to Haydock Park, then the reverse on the way home), therefore adaptive cruise was on my 'must have' list, hence getting the 4hs. Found it was absolutely invaluable on the M1 last night, where there was a 50mph speed restriction, and traffic was flowing (calling it 'flowing' is a stretch of the imagination, I'll admit...) at between 0mph and 40mph. Set the cruise, and just go with the flow... And the FCM (forward collision mitigation, I think it stands for) was great. When everything came to a complete stop, it stopped the car for me. Now, if Mitsubishi introduce a self-steering PHEV....
I have been told that the 5 year warranty started in March 2015, so all '15 plate PHEVs have the 5 year warranty.
I like the auto openning boot - no more dirty hands when the car is filthy, or juggling boxes and bags trying to open it manually... The reversing camera makes life a lot easier. This was another 'must have' for me, as I'd been used to it on my Toyota Prius and Lexus CT200h. The heated seat is wonderful, especially if you've got a nagging backache!
You may also find the price a lot cheaper for the pre-facelift version. This is what I got in the end. Paid £6k less for a car that was 6 months older, but with 7k lower mileage than a facelift model on the same forecourt. I have also been told that it's getting increasingly difficult to find the pre-facelift 4hs, as they are so popular.
I would probably suggest that if you have the choice between two cars, go for the higher spec one even if you don't think you'll use the extra options - you might be surprised how much you do.