Bhfromme, since you note you're looking to acquire one or the other, even though I love my Python, I would recommend the 586. You'll pay less for it than a Python, and you'll get a really good gun.
The reason I bought my 586 no dash is because I'm a bigger fan of the older Smiths than I am of the current manufacture versions. If you can find one that looks like it's been used little (586-0 through 586-2), I think you'll have a winner there. With the 586-0 and 586-1, make sure they're marked with the "M" on the frame by the model number to show that the gun had the warranty work done.
The reason I bought my 586 no dash is because I'm a bigger fan of the older Smiths than I am of the current manufacture versions. If you can find one that looks like it's been used little (586-0 through 586-2), I think you'll have a winner there. With the 586-0 and 586-1, make sure they're marked with the "M" on the frame by the model number to show that the gun had the warranty work done.