Personally, I'd go with the 3 inch 629. While I have some long barreled revolvers that I enjoy shooting they just don't get me going as much as shooting a shorter barrel. Fact is my 6 1/2 inch 610 is a bit of a tank and distinctly muzzle heavy so it gets tiring after 100 rounds or so. On the other hand I'll shoot my 4 inch 625 until either I run out of ammo or the cylinder gets hot enough I can't close it without gloves.
However, if I ever do break down and purchase a 44 Magnum you can be sure of one thing. That is that I would never shoot a 44 Magnum with it. I've already determined that my particular limit for recoil is the 357 Magnum and wish to preserve my wrists as long as I can. If I were 20 years younger I'd probably think differently, however I've finally come to the age when I realise that I just don't need to beat myself up just to do it.