Nurse - the 412 is no bigger than the Puma and is a far less capable airframe. BTW, what happened to the Puma 6 stretcher fit?
I've flown all three types. The 412 is an ancient design and really quite limited in performance. The RAF Puma (God bless her) is a late 1960s design too, some of the RAF airframes in use are close on 35 years old! The helicopter equivalent of driving a 1970s car in a Formula 1 race?
I would have no hesitation in deciding which I'd rather fly in an operational theatre - Blackhawk please, every single time! After all, it's a 10,000 kg airframe with an impressive performance with the 701C engines. RTM322 (over 500 more shp) would turn it into an even more potent machine and give room for future development, especially now that engine has proved itself in service.