Do you want Happy Entry at Disneyland and the Disney theming?
I have not stayed at Celebration but a lot of my friends have. Celebration is quite a bit away in the middle of nowhere. You'll be reliant on the buses to get to/from the parks and at closing, the wait for the bus can be like 1/2 an hour sometimes. The main reason to stay here is to get in to Disneyland early but you'll have to wake up extra early to do this.
The Sheraton was my go-to hotel pre-pandemic. It's right across the street from Bayside station which is right in between Disneyland and Disneysea on the Resort Line loop. It's faster to get to the parks and based on my friends' descriptions of the rooms at Celebration, the Sheraton is nicer. But you won't have Happy Entry at Disneyland.
If you're going to go into Tokyo without switching hotels, I find going to/from the Sheraton easier because you take the resort line to transfer to the JR lines. From Celebration, you'd take a bus to Shin-Urayasu station which is one station further from Tokyo.
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