What a fantastic property. This is now absolutely my favorite Sheraton property that I've visited (better than Prague or Poznan, which are both quite good). I had two rooms booked, one of which was upgraded to an Executive Suite. The check-in staff were incredibly friendly and helpful, and the location of the hotel was not really an issue (cabs in Porto are, as was said above, dirt cheap). Porto is an incredible city, and it didn't hurt that there was no shortage of excellent wineries and Tavernas to visit.
Below are some photos from the Executive Suite I was given:
Suite Bed
Suite Work Desk
Suite Dining Nook
Suite Living Room
Suite Bathroom
Suite Shower
View from Suite at Sunset
Beautiful Porto (taken from Gaia, about a 7 EUR Cab-Ride from the Hotel)