The Redhawk and the 629 are both great guns, backed by excellent service. You wont go wrong with either one, for a lifetime. Still, however....
Weight and bulk: On the Redhawk, you will have to change the grips, adding at least 4 more ounces. You end up about 10 ounces heavier than the Smith, which is more than a roll of quarters. Then load it.
Endurance: I had an Endurance Package 629-4 that I ruined with heavy loads. But my Redhawk didn't endure heavy loads all that well either. After about 500 rounds of 300gr with plenty of W296, the cylinder didn't want to latch right. Heavy loads caused it.
Recoil: My 629 is 7 ounces lighter than my Redhawk, and the Redhawk is Magnaported. But there is still not enough difference in recoil to want the extra weight.
Just me, but I hate heavy guns. That's how I ended up preferring the Smith.