I just got back from a 15 day trip to Egypt. Stayed at the Marriott, Ritz and Sheratons there. Here is my opinions about the Marriott and Ritz.

Cairo: Cairo Marriott (Zamalek). It's a category 4 hotel. They recognized me as Platinum and offered me the Platinum welcome gift. I chose the fruit and ice cream. They sent us enough fruit to last us (2 people) for 5 days and plentiful of ice-creams. The room was the usual Marriott room with a Nile view. Platinum status gave me access to their lounge which had free breakfast, the breakfast buffett was quite extensive and very good. Nothing memorable about the hotel, if you want a taxi from the hotel - don't catch one from the hotel, walk out of the gate and catch one; the fare difference is amazing, sometimes 25% of that inside the hotel. There are few restaurants in the hotel, didn't try them but did go to the Marriott bakery. It's supposed to be one of the best in Cairo. The prices are the same as US prices; it's a place where the Cairo rich n famous come.

Sharm El Sheikh: Ritz Carlton. The Ritz is outside of town sitting on a beach front property. The hotel is quite a fancy place. They don't recognize Marriott Platinum; they gave me a suite, which was OK - no beachview. I paid 250K Marriott points for a 5 night stay. You might consider checking the rates on the property through an Egyptian travel agent they are extremely reasonable, better than spending points.
Free breakfast is included and what a breakfast!! You sit in a restaurant overlooking the Gulf of Aqaba with your breakfast from an exquisite buffett. There are free shuttles to Na'ama bay which has a Las Vegas style strip. Several restaurants in the hotel, expensive by Egyptian standards, but not if you are used to USA prices.
The beach is very small, the swimming pool is really nice, good snorkelling just off the hotel beach (no gradual slope here).

If you have any questions, let me know. I will be glad to answer them.