The Sun hubs have 3 pawls, the Hope Pro 2 have 4 pawls. Having more pawls allows the free hub to have more points of engagement, however not a lower degree of rotation before engagement. More points would theoretically be more robust since you won't be applying the load to more points, however, more pawls also can mean more drag on the hub.
The number of pawls is the obvious difference between the two, the general hub designs are similar though. What I don't know is if one brand uses better quality materials, has better seals, is easier to service, etc.