different point of view. I think it depends on time of day and time of year. I'd take DFW in winter. ORD in spring or summer - especially if a later afternoon flight (storm time of day).
For either airport, I'd look at what the backup flights were if you miss a connection.
A delay at either is bad to make a flight. Personally, I prefer ORD. I find the G to HK much easier and more in my control than DFW.