buckhorn, that the gun would be a "snub nose" the difference of a 7lbs and 9lbs trigger is nothing to me. I find stacking to be the biggest detractor from a D/A pull than overall pounds.
so aside from a still very serviceable trigger (in my hands anyway) there is no difference to you? when you say slightly lighter and slightly smaller how much are you talking?
Trying to describe this on the Internet is like three blind men describing an elephant...it just doesn't work.
You need to go to a gun store and handle the guns themselves and make up your own mind.
You've never said why you're buying the gun or HOW you plan on using it. Let me give you several examples.
I bought the Ruger Alaskan for one reason - field use in northern Montana and Idaho where you may run into brown bears. I needed a smaller pistol that I could carry in a belt holster that would not impede me getting in and out of my truck.
I have a .460 X-Frame, but the only way you can carry that easily is in a cross chest holster - which sort of rules it out for all day carry in-and-out of vehicles.
The Alaskan is the answer to that specific use. I load the Alaskan with 305 grain, hard cast flat nose bullets. I would NEVER shoot those regularly (practice + field use) out of an S&W M629 - that type of load just puts too much stress on the 629's lighter frame and cylinder.
The Smith is lighter weight and has wood grips which makes recoil feel far worse, and gun control for follow up shots harder. The Ruger Alaskan is better for recoil and gun control as the gun is heavier, and the factory grips are made to reduce felt recoil and assist the shooter in handling the gun better.
If I want a lighter weight .44 caliber revolver for field use, I carry a M624 .44 Special with a tapered, light-weight, 2-inch barrel, that has a drop butt grip - it was a special run made for Lew Horton (gun distributors) in the mid-80's.
It weighs 37 ounces unloaded, and 42 ounces loaded with 240 grain bullets. The rounded grip is smaller than the standard S&W grip which makes it easier to wear under a jacket, and doesn't snag when you need to draw the gun. You can still find them for sale now and again on Gunbroker.
As for the M629. The one I have has a 4-inch barrel. I bought it because I like .44 magnums and wanted one with with an intermediate length barrel. This one was relatively unused, was an older model that has a trigger that can be tuned, and was the right price.