Go true to size. (ie: I am a true size 9.5 so I buy my 730s in a size 9.5)
The 730 does NOT come in different widths.
Comfort Factor Ratings:
Softness: 6/10
Firmness: 7/10
Midsole shape 5/10
The 730 almost has a great balance between softness and firmness, but it does lean more on the firm side on feet. It also has a pretty average midsole that isn't the most supportive. It's okay for a lifestyle model that is decades old, but don't compare it to newer NB models.
The 730 utilizes a dual density eva foam midsole. This shoe predates ENCAP and Absorb.