As hard as the 617 is to find right now, it's kind of difficult to find either so you had best take what you can find if you stumble on one.
However, I have the 6 inch version and as others have posted, it is distinctly barrel heavy. If you want something that would be ideal for training new shooters, woods carry, and cheap DA practice I would recomend the 4 inch version or the model 18. I also suspect that if both version were equipped with Optics, you would not see any benefit in accuracy from the longer barrel. However, without Optics, the longer sight radius of the 6 inch version makes it much easier to shoot a tight grouping. In addition, you'll also get a slight boost in muzzle velocity with the longer barrel, so it might extend your effective range on small game by a bit.