The changes in the 686 Pro Series aren't that great.

The chamfering done is quite mild and needs to be increased compared to good competition guns.

High-hand-hold grip might help, but if one holds the gun properly the high-hand-hold can be had with any grip.

A bossed mainspring is about a $10 value.

I cna't comment on the bbl and crown. I have my doubts on the amount value this provides, if any.

I'm also not a fan of the sloped barrel profile aesthetically. Though the less weight could help in competition slightly.

S&W claims no improved trigger on the Pro (other than the $10 mainspring). If they could market a better trigger they certainly would. They don't. Tirgger is no different.

Having said all that, there is not a large difference in price. Understandably, as there isn't a large difference in value provided.

There is one big benefit provided, and it likely is worth the added price - the interchangeable front sight. That's a wonderful option and can save a nice bit of money and/or hassle. Wish this was on my regular 686.