Having 629s in 5", PC6", 6.5", and PC7.5", their primary purpose being a backup and/or complimentary sidearm when deer hunting or ATV sidearm. For that application, my preference is the PC6" mostly because it was a limited run and has an integrated scope mount should I chose to plop on a red dot when I the treestand. I wouldn't hesitate to carry the 5" mostly because the 5" and 6" are easier to carry than either the 6.5" or PC7.5".
The 5" is an overall good compromise unless your plan is to load it up with 300gr+ bullets, then the longer barrel length/weight would help with recoil.