I my opinion (and others in the business) the Ruger DA revolvers (Security Six series (not made any more but can be found), SP101, GP100, Redhawk, Super Redhawk) are stronger than the S&W's because they have no side plate and seem to be better able to handle high pressure rounds without loosening up because they are so robust. That said, the S&W trigger pull is probably better than the Ruger (but I've been hearing complaints about it with guns made in the last 5 years or so). BUT, you, or a gunsmith, can really slick up the Ruger action with a little polishing work and replacement springs.
The Ruger is also MUCH easier to work on the internals because of how they are made. S&W lock work has a lot of small pieces that you have to worry about if you want to work on it but the Ruger hammer and trigger assembies come out in one piece and are very easy to work on.
Put a L frame S&W (Model 686 .357 Magnum) and a equivalent Ruger (Stainless Steel GP100 .357 Magnum) in front of me, I wouldn't even think about it and would take the GP100. Then pass it on to my children, and they pass it on the their children, and ...