The lounge at the Sheraton is poor. No room upgrade when I stayed as a Platinum. For some context, it used to be a Category 2 hotel, but the award category has been rising along with Osaka room rates...

It does have reasonable transport links though. IIRC it's right next to the private train line to Nara, if that is on your list of places to visit. It's an easier day trip from the Sheraton than it is from Kyoto.

I've also heard good things from a friend about the Courtyard and its lounge, especially as a base for day trips to Himeji, Kyoto, etc.