The advantages of the resin frames are: lower production costs, and light weight.
S & W produces an aluminum framed .38 in the same weight range and it costs a good bit more. Of course S & W guaranties the frame for life; I'm not sure about the Ruger guaranty.
The .357 Ruger has a steel frame and is heavier (but still cost-effective and fairly light).
S & W makes a .357 scandium framed snubbie but it is very expensive (about $1,100.00 list; locally just under $900.00 here; and at Bud's guns just over $700.00) but very light (under 11-1/2 ounces).
I read a test (torture test) and the Ruger did relatively well, but the author recommended against a steady diet of +P rounds.
Of course resin framed revolvers are fairly new and they don't have the favorable history (yet) that resin framed pistols have. So if you are of a conservative nature you might want to think twice. But overall the write-ups I've read say the Ruger is an excellent gun and the resin frame seems to absorb some fo the recoil making it easier to shoot.
And Ruger (as a corporation) has always seemed to be conscientious about standing behind their products.