Mercure Centre Hotel can be booked online via agoda or booking.com. Frontdesk staff are not all friendly/helpful but the bed is very comfortable and the sheets are soft. It's quiet throughout the night, but you can hear other guests/morning calls in the morning. Wired internet is a tad slow but is free. Pool on the 5th floor's a good size and heated in November so it was nice to take a dip there. The safety deposit box inside the room is also good.
Info on booking website states it's within walking distance to "Marina Mall". It is NOT. It's less than 15 minutes by taxi and costs about 15 AED. We waited 20 minutes for the hotel shuttle bus to drive us from Marina Mall back to the hotel but it never came. I called the hotel but they were not helpful at all.
The Chinese restaurant on the 2nd floor has decent food. It was about 80 AED per person (1 appetizer/soup, 1 main dish, rice). It was very smokey inside though. Burger King is a 2-minute walk down the street and there's a Starbucks across from that. Lulu Hypermarket, a supermarket, is across the street from the hotel.
It is about a 10~15-minute walk to the "Madinat Zayed Shopping & Gold Center". There's a Daiso inside (Japanese store where everything is 7 AED). The "Abu Dhabi main bus terminal" is less than 10 dirhams away by taxi. From there, you can catch buses to Al Ain (2 hours at 10 AED), Dubai (2 hours at 15~20 AED), and Ruwais/Ghayathi (3 hours at 12+2 AED). The taxi hub is also there. Al Wahda mall is right by the bus terminal. It's a nicer mall to go to.
For taxi drivers who don't know where it is, tell them to go to "Hamdan Center". By taxi from the hotel, it costs about 25 AED to go to "Sheikh Zayed Mosque" (about 20 minutes) and about 35 AED to "Souk Qaryat Al Beri" (higher scale shopping complex with ocean-front restaurants). It's less than 15 AED to go to "Emirates Palace" by taxi.
Overall, I think Al Rawda Arjaan by Rotana is a better place to stay.