Picked up my new LNIB 3904 this afternoon after having never held one before. Wow!
I had a 3913TSW with rail I could never get used to and sold it. Had a 908 that shot great but could not get used to the "blockiness" of the slide. Got rid of it.
I've got plenty (my wife would say too many) 3rd gen Smiths but prior to this one only a 39-2 and CS9 in single stack.
This one may quickly become my favorite - slim yet large enough to get a purchase on the grip. My 39-2 is just too nice too carry.
Pictures and range report forthcoming.