While I am not a long time collector like a lot here on the forum (about 27 years) my collection has centered around the Ruger DA's. One has to remember that William B. Ruger (a HUGE firearms collector) did not want his guns to be for collectors only, he wanted (and made) firearms to be used by everyone and that they must be reliable. So, they may not be the prettiest guns around, although Ruger did and still does make runs of "special" (I don't necessarily want to say customized but many are) firearms that the fit and finish are on par with any ever made.
Personally, I have not seen an upswing or a decline of the quality of the DA's over the years and I have examples of all of them. I specialize in the Six series, both low back frame and high back frame and many people believe that they were the best DA's Ruger made. I would have to disagree (very slightly

). The Six series were made in the early 70's to late 80's and manufacturing concepts and procedures are always changing and Mr. Ruger in many ways led the charge in how firearms were made. I believe that the quality of Ruger firearms has always been extremely high. Yes, there have been some problems with some firearms, but tell me what mass manufacturer of anything has not had some problem children get loose. Just read gun forums, the Ruger naysayers will always nit pick a Ruger to pieces and say "I told you the quality was bad".
Again, I have not seen wholesale bad/poor workmanship on any of the Ruger Double Actions. In fact, I just got a Ruger that the fit and finish, in my opinion, would rival that of a mid 60's S&W or a Colt Python. It is called the GP100 Royal Phoenix. It was a special run for Lipseys back in 2010-2012 and would say the quality is there. This picture taken by me does not do this revolver any justice, sorry.
I really don't see any degradation in Rugers DA revolvers from what were made 50 years ago to what is being made today. Manufacturing is different now and things will look different but that doesn't mean they aren't quality firearms. Want to start an argument? Go on a gun forum and ask why people don't like MIM parts

. Those that purport that MIM parts are far inferior are people who have NO metallurgical background or training. Sure Ruger has had problems in the past but they always overcame them.
I work on guns as a business, and specialize in Ruger Double actions. Ask me what DA revolver is the easiest for a layman to work on - it won't be a Colt Python, or a newer generation of of S&W. That being said, if you work on anything almost exclusively, it gets easier and easier to do. But out of the box, for a novice shooter, I would say the Ruger DA's are the easiest for someone with basic mechanical abilites to perform maintenance on.
To sum it up (and I could probably keep writing but it would be easier/more enjoyable to sit and discuss with someone), Ruger double actions are made very well, have been made very well in the past and probably will be made very well in the future. Even die hard S&W and Colt owners I know who have Rugers say that you just can't wear them out.