There are 4 Marriott brands on the website now, Not real sure about the 'old' Sheraton or the new Fairfield in the city.
But did stay at the Courtyard in west Qinhunagdao and the Marriott RESORT in Beidaihe after the Golden week season in October for 2 nights at each of these properties. Both are new & modern & have been open about a year & a half now.
The Marriott 'resort' is fabulous. (web site pictures are true) the two pools are great, one inside & the outside infinity pool, both are on the 11th floor. The rooms are either ocean view or ocean front, both have balconies. Some rooms have cat themes for those with children. Only a few ocean suites with a terrace and/or so-called parlor room suites. It's a "resort" so no EL, but beautiful buffet breakfast area on 1st floor, also the weekend seafood dinner buffet (only $25) has local seafood and great dishes. There are 2 bars, one in 1st floor lobby which sells coffee and snacks in the morning, the other on 11th floor by the outdoor pool that opens at 6 pm with live music about 8pm. The building architecture design & technology are amazing, except for the poorly designed car drop-off and parking areas. But there is public parking on the nearby street or a daily (pay by wechat) parking very near the public ocean beach. An oddball issue here is the hotel and nearby conference center do not have a business center, but its sure an amazing ocean resort hotel on a 'clean' beach with a neat boardwalk + ocean pier.
Oh, the nearby KFC and Pizza Hut were closed as the summer season at Beidaihe was over, but the local Moms coffee shop/kitchen was open on the beach on this October weekend.

The new Courtyard is located in the local government center and the new technology development area. (thus, not much city nearby) Normal breakfast buffet for a China Courtyard on 2nd floor. The EL on 11th floor has local food dishes (3-5) and beverages at 6 pm. El is open from 9am-9pm managed by Anxin. The EL has a small conference room and business center. Anxin did confirm my reservation a day ahead on both wechat & by phone. My room with tax was only $50 a night, WOW, considering the inclusive Mrt elite food benefits of breakfast and EL food & beverages. There is NO pool here at this Courtyard, but corner rooms are very modern, mine had 2 Tv's (with 4 english channels) and 1 1/2 bathrooms. One bar in the 1st floor lobby was not very busy, but beautiful lobby. Realistically, this hotel was built for local government and potential Real estate buyers who might stay for several days/weeks.( the train station is about 20 minutes and about 50rmb taxi) All the Courtyard staff are well trained and very helpful. Chinese name is Xinji Wanyi Hotel.