Personal needs, desires, and income...
Having gotten rid of my last Model 19 back when $250 was a good price for a 6" blued in fine shape, my opinion is somewhat skewed by my personal situation.
What is a "good" or "fair" price for many guns has gone up so much recently, that frankly, I not happy or often willing to pay "going rate". Especially for a model 19.
Don't get me wrong, Model 19s are nice guns...BUT they aren't anything really useful, for me. Since I only carry when I want to (as opposed to having to wear one 8+hrs a day, duty style), and since the 19s are not suited to the full .357 Magnum loads (not what the ammo companies are selling now, but what it was back in 1935 or so...), AND 19s are what I consider just over the big end easily concealable, they aren't anything special to me.
That being said, if you are only planning on one gun in .357, the 19s are a reasonable compromise, and if you want one, you have to pay what the market asks. Deals are still out there, but not so easy to find these days.
All else being equal (and it almost never is) bigger bullets tend to work better.