I too have a PHEV (Cooper S E All4). It's a 2018 model and apart from the abysmal lack of Android support I'm very pleased with it.
Depending on the green incentives where you live and your driving pattern it might make sense. Goes like a little rocket up to moderate speeds (around 100km/h 60MPH), and makes perfect sense for me as I do a lot of trips within electric range. For someone who makes a lot of long, high speed trips, it wouldn't. If you like performance at higher speed you'd be better off going for the 4-cylinder, 2-litre Cooper S or JCW, while if you want a more economical car over longer distances, and don't care too much about performance, the regular, 3, cylinder 1.5-litre or diesel Cooper would make more sense and are nippy enough for most drivers.
The 3 cylinder engine is a gem and has won awards for its quiet smoothness and flexibility. It is also economical, but don't expect miracles when hauling around a car like the Countryman PHEV, which weighs over 1700kgs. As an added bonus the 3 cylinder makes a lovely noise when revved, though not quite as good as the crackles and pops of the JCW 4 cylinder!
Technically, the newer Minis are much better than the previous generations and are now simply re-skinned BMWs.