The 580 has a bigger toebox.
Go down half a size from your true size (ie I am a true size 9.5, so I buy my 580s in a size 9)
Comfort Factor Ratings:
Cushioning (Softness): 5/10
Stability (Firmness): 6/10
Cushioning to Stability Ratio: 5:6
Midsole Shape (Support): 6/10
The 580 utilizes Abzorb, C-Cap, and Rollbar technologies in the midsole. The most prominent technology in the 580 is Rollbar, which is designed to be a post stability system to help control rear-foot movement and enhance support.
The 580 is more firm rather than soft in the heel, but there is still a decent amount of softness in the front and middle of the shoe. The midsole shape good for a retro runner, as it is not entirely flat. It's on par with other retro runners' comfort and is okay overall in terms of comfort.