Of all of the 3rd generation S&W Autos―which are some of the best guns ever made IMO―the 5906 is my favorite. I have two of them. One is NIB and the other is my very first duty weapon carried when I was a brand new, ''wet-behind-the-ears'' Deputy Sheriff.
The one model that I really regret never acquiring was the 1006. If I can find one in superior condition (that isn't priced as if it was made of pure gold), I'll likely pick it up as it is one of my two 'grail' guns.