I have a 23 inch 17 HMR barrel for my Contender and like it.
Encore barrels chambered for rimfire cartridges have a hump on them which I think looks a bit weird. Since they look weird, I wouldn't buy one; yes I know, probably not a good reason. The other factor to consider is barrel length vs cartridge case capacity. Increased barrel length increases velocity to a certain point, depending on case capacity, after which increasing the length more will cause a decrease in velocity. I'm thinking that if you went with a 28 inch Pro Hunter barrel, velocity might actually be lower than with a 23 inch barrel.