I almost always only stay at Sheraton hotels for work, either because rates at my preferred nicer hotels are too crazy or because there is no other nicer option in smaller towns/markets. I also rarely use or care about the infamous lounge; I care far more about how good room service or the hotel restaurant may be.
Pleasantly surprised Sheratons:
Sheraton Hartford South--a shockingly good bar and restaurant, always clean and comfortable rooms, and a staff always trying to please. I don't mind staying here ever, which is surprising for me. Nothing nearby, but it's so good I don't mind.
Sheraton Boston--a surprisingly attentive and well run massive conference hotel. It's huge, and yet I've almost always had nice service, good rooms and upgrades, and reasonable rates. Location is also excellent.
Sheraton Wild Horse Pass--a newly renovated, clean and up to date property and absolutely beautiful location, with good reliable service. Feels like a resort.
Sheraton Grand Los Cabos--never stayed, but visited friends and had surprinsgly good food, drinks, and service, and our friends' rooms were spacious, well appointed, and had nice views. Surprised me.
Sheraton Grand Sacramento--always have nice stays, food food and beverage, nice spacious rooms/suites, and good service.
Sheraton Kona--suprisingoy good service for a stay many years ago, good rates, good food, subpar grounds, solid air con...but I enjoyed the stay.
Solid and pleasant Sheratons:
Sheraton University City Philadelphia--was under second reno in spring, curious to see if improved. Good service usually but not always. I've used this lounge, and it's not bad. Love the noodle restaurant. They always upgrade me to suite, even when I'd rather they didn't.
Sheraton Tel Aviv--could use refresh but conveniently located and not had service. Ocean views even. Nice location.
Sheraton Fisherman's Wharf San Francisco--solid service, convenient location for trips out of the city in either direction, reasonable rates usually, decent clean rooms, decent food/beverage, like their lobby lounge.
Not good Sheratons, places I avoid if possible:
Sheraton Downtown Philadelphia--had all the bells and whistles but I hated my room
Sheraton New York Times Square--small rooms, lines at front desk, massive factory hotel, phone bureaucracy nightmares, elevstor nightmares, service suffers by default. Great doormen though.
Horrible Sheratons, you couldn't pay me enough:
Sheraton Universal City Los Angeles--it's just atrocious.