Great location if you're willing to stay in downtown but away from the "hills" were it is usually more crowded and where it is harder to reach (by car). We are a couple on our 30s and loved everything. We are locals, used to live in Lisbon (nearby) and now live in Sintra. Parked in the nearby underground parking at 21:00 and left around 11:00 and parking was 24,50€. We've only spend the night there as a quick "kid-getaway" trip.
Breakfast was alright as well, pretty much the "every hotel standard" of croissants, bread loafs and sliced, scrambled eggs, beans, bacon, sausages, muesli, juices, etc. Maybe here you could do something different, like adding different "paid" choices like eggs on toast, waffles, pancakes, etc. :) (our suggestion) anyway, the current will please most people used to travel.
Bonus: decoration is different from classic hotels, that's a great plus for us!