I've owned two model 66's, a 4" no dash with stainless sights, and a 2 1/2" dash 1. Sadly I sold the 4" 40 + years ago. I still have the 2 1/2" version, and have every intention of keeping it.
The model 66's have all the advantages of the model 19's, along with the added advantage of the stainless construction. If you really want a model 66, get it as soon as you can as prices are going up.