I've not yet put more than a few hundred rounds through my GP100 (.357), which is for most purposes a redhawk, so I was basically looking at the same line of decisions myself.
The Taurus guns I eventually decided against because of how loose all the used ones ones I picked up and looked at were. I'm sure they still functioned fine, and the do have a no-questions asked warranty, but it turned me off from them.
I was torn between the Smith and the Ruger, eventually going with the Ruger for the simplicity.
I've had Smiths an I would never ever attempt to take them apart past taking the side plate off every blue moon to spray it down. You'll have to go to the gunsmith with a bag of parts otherwise.
The Ruger though? Amazingly, it's as easy to take apart as most semiautomatics.
I pulled my apart and applied some 800grit wet dry to all moving surfaces, grabbed a set of shims and Wolff springs from these guys:
http://michigancenteroutdoors.com/ruger ... ction.html
Trigger immediately turned into a dream for a few hours of work at $22 of parts? Now THAT's a selling point.
Plus, they are tanks.