Stayed at the Sheraton Lisboa recently for 5 nights. Good experience overall. Staff were great and very good in dealing with any requests. The room was decent size and comfortable. As Marriott Gold, I didn’t have access to the lounge so can’t comment on that.
The hotel location is good with lot of shops and stores nearby. There’s a nice cafe (Simpli cafe or something like that) right across the street for a quick coffee and various other bakeries, cafes, and restaurants also nearby.
Easy 20 or so minute walk to the Rossio train station and various touristy parts of town.