I bought a 59 new in 1979, and I've always liked it very much and shot well with it. As AK mentioned, I do have long and slender hands, so the larger grip frame works for me. This is why I also really like the Beretta 92 and 96.
In contrast, the 39's grip frame feels too sharp-edged and board-like for my hands. This is also a problem that I have with the 4506, and is the main reason why I never bought one of those. 59's don't seem to have the almost cult like status of the 39's, but they're good guns and I prefer them. I also just like the fact that they're S&W's first hi-cap nine.