The right hotel is the one that makes the flight home boring. On a short layover that usually means Bur Dubai, Deira, or the airport itself, not a resort on the Palm.
Prices swing hard around holidays and big events. Book a flexible rate if the inbound flight is the thing most likely to move.
At DXB
Choose an airport hotel when the onward flight leaves before about 10:00, when you land after 16:00 and depart the next morning, or when you simply do not want a 05:00 metro.
You will see less of the city. That is the point. A short Creek trip is still possible if the afternoon is free, with the room as a retreat rather than a Downtown address.
This is the default layover base. You are on the Red Line, close to Al Fahidi and the Creek, and the ride back to DXB is the short one.
Ask for a room that is not facing a main road if you are sleeping at an odd hour. The neighbourhood is lively, which is what you want at dinner and not at 02:00.
Worth it on 48 or 72 hours if Downtown is one of your two blocks and you want to walk to the fountain. It is a longer metro ride back to the airport than Bur Dubai.
Do not pick it for a dawn departure. The skyline does not help you at 05:30.