In general, Ruger for new guns. I do like certain older S&W revolvers, and not just the ancient P&R'ed revolvers. S&W went through eras of greatness, one being right before the MIM parts started. MIM itself is OK, but an MIM trigger itself is wide and blocky, and because it is hollow-backed, does not have enough "meat" to allow it to be sculpted to what I like. With the keyhole lock, plus MIM, S&W revolvers went from being works of art to mere tools, like a Dewalt drill or something like that. I like my Dewalt drills, but they are not works of art.
The trigger on Ruger DA revolvers is perfectly shaped for me. The stock SP101 grip is near-perfect for my hands. The pre-Hogue GP100 factory grip IS absolute perfection for my hands. Finding a Ruger with a smooth action does mean some shopping around, at dealers that have enough stock for comparison. It helps that I find SA to be irrelevant in most DA revolvers, so I just shop for DA smoothness.
FWIW, a snapped mainspring, in my personally-owned duty S&W Model 58, is one of several reasons I now rarely carry only one gun, but notably, Rugers use coil springs, which virtually never break. I do still trust an S&W, but not as completely as a Ruger. Anything mechanical CAN fail, but Rugers have that one point where they are less likely to fail than medium- and large-frame S&W revolvers.