DFW Grand or HR
I've stayed at both on site Hyatts within the past year and definitely prefer the Grand. At the time I stayed at the Grand, the price was nearly equal to the HR so it was a no brainer. On a future stay there was a significant difference in the rate and since I was on business and could not justify the difference, I booked the HR.
Both were good stays but the Grand is definitely a step above in terms of quality of the rooms and service (including service in the restaurant).
So as a previous poster pointed out, check both and let the price difference be your guide. I would personally pay up to maybe $20-$30 more for the Grand depending on the length of my stay; otherwise I'd book the HR.