I've happily discovered that Google Fit now has an option for pairing with a Bluetooth heart rate monitor-- picked up a polar H7 on Amazon, and it easily paired with my 45-- I now get a nice graph of heart rate during my workout-- very slick and reliable.
I'm guessing more accurate than Apple's solution, no matter how much marketing is applied!
Also hoping for a new Connected this year, would think more likely around March, exactly 2 years after the current 45.
I also sprung for a Calibre 16 analog module this fall-- it is indeed very nice and will outlive my 45 and make use of the rubber and titanium straps I have collected over the past few years.
JCB, with intuition, got it right -- great reliable product.