I have the opportunity to buy a new old stock 44mm gold stainless series 4 watch for about half list price. I already have a series 3 Nike edition. I am not 100% in love with the gold stainless but I figure I will outfit it with a nice leather band for a dress watch. Is the series 4 still a reasonable choice. It seems that the series 5 and 6 have been pretty incremental in their updates with alway on and blood O2 being the 2 biggest new features. Thanks for your thoughts.