I have one of the new 66's.
Great gun. My only complaint is the trigger is stiff, but then, it's a new gun. It doesn't have 20 years of firing to smooth it out yet. I do think it's a better candidate for a long life of magnums; the ball detent and the lack of a flat pot in the forcing cone can only help it stay in good shape over the years.
If a person wants to shoot magnums and doesn't want to move up to the L frame 586/686, I'd recommend it over one of the older ones. You aren't going to have the concern about hot loads that you might have with the previous models.