FlyerTalk Evangelist
Join Date: Aug 2011
Location: Barcelona, London, on a plane
Programs: BA Silver, TK E+, AA PP, Hyatt Globalist, Marriott LT Plat, Hilton Diamond
Posts: 13,057
Best use is a personal decision.
There aren't any hotels worth flying across the country for a single complimentary night. There are lots of Hyatt hotels in locations that you might really want to visit. There are also lots of really nice hotels in places you have already visited dozens of times (and don't want to repeat).
You need to be more specific about what constitutes "good use" for you. Looking at the list of Category 6-7 hotels is probably easier than trying to explain it on an internet forum.