Stayed at Penha Longa recently and found, in the all, a very pleasurable experience.
We were there for four days in total at a conference. The conference facilities were excellent.
We didn't play golf nor walk into Sintra. We did find, however, the hotel to be far away from anywhere which some may like, some may not. For my part, I think that whilst the hotel no doubt plays on the benefits of this, they also cash in on the fact that nothing is close.
Wifi is free (albeit restricted) in the bar area, however, venture away from there (including your room) and the only option you have is to pay €18 per 24 hours for access (or €6 for an hour!). I found this quite disgraceful.
Also the cost of even drinking a bottle of water in your room is €3!! A pint of Superbock at the bar is €9. I did have a pint after fainting!
The room itself was fantastic and I had no reason to complain about the cleansiness or operation of the hotel staff - all were fantastic and met our every need.
The food was very good where the conference was concerned. At one point I ordered room service and I must admit €18 for a small pizza which was inedible was a bit much.
That was my experience but I hope it is not repeated for others - the parts of the hotel that I did not experience I feel I really missed out on and would love to go back and prove myself wrong at some point.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC