I love big bore revolvers and own a number of them. I own the 4inch redhawk, 629 and traded an Alaskan in for something different because I had the 4inch. I am not going to discuss the characteristics of each of them here, because I have written reviews on my website.
What I will comment on is all the talk about durability between Smith and Ruger. My opinion is either of these will last the average shooter a lifetime. What makes this complicated is that word lifetime it's subject to be challenged, what is a lifetime? To some it is 1000 rounds of 44, to others its 5000 rounds of 44, to some it may be 30 to 40,000 rounds. Though I don't know of or have any concrete data, the price tag of 44 Magnum may keep the average American from shooting it as often, maybe 10,000 rounds in a lifetime if you purchase or reload. Having said that here is a review of a 629 after 5000 rounds, which also includes a link to the initial review upon purchase here on my site.
S&W 629 After 5k rounds
Yes there is no doubt the Ruger has a thicker cylinder and frame. But this is always mentioned along with the statement of I can load hotter rounds through a Ruger. Not bashing anyone but I have never understood that and yes I do reload have been for over 18 years and know about Ruger only loads. But If I wanted to go above SAAMI spec, risking my health and someone else's for that matter why not just be safe and go with a larger more capable caliber like the 454Casull, 460 or 500 all which are a hoot to shoot
The additional gain in velocity is not worth my personal safety. Again just my opinion.
If interested here are some links of reviews for the ones you are considering.
Ruger RedHawk 4inch
Others not being considered but may help you gain more insight and make a better decision.
S&W Performance Center Model 29
Ruger Alaskan 454
Ruger 4inch 45 Colt
Also be aware changing the grips on my Redhawk 4inch was a pain as the plastic disk insert has been changed with this model and will not fit regular redhawk grips. To make standard Redhawk grips fit you need to call Ruger and tell them you need the large disk. They new exactly what I needed when I asked, but they were out of them. Though as soon as they produced more they shipped me one for free, took about 3 weeks.
Hope this helps and good luck.