We stayed at this hotel in February 2005. It has some definite pros and cons.
The cons: it's not directly on the beach, so it doesn't have any big "views" or direct beach access (the hotel is oriented around a nice inner courtyard/pool area). Rooms were on the small side. The Plaza is an older luxury hotel so it doesn't have the ambiance or services of a newer / more expensive hotel (like the Sanur Hyatt down the street).
The hotel at the edge of the Sanur tourist area, so it's a longer (and hotter) walk (or a short cab ride) to the Sanur main street (shopping, restaurants). The Sanur tourist zone is smaller than the Kuta zone, so it's less "first world / fully westernized" than Kuta is, and has fewer restaurants, shops, bars, etc. The Sanur beach is OK but overall not as nice or pretty as other beaches (Kuta, Nusa Dua, Jimbaran). There also aren't as many water sports options (parasail, banana boat, diving, etc) at Sanur compared to Nusa Dua.
But this hotel has a lot of pros: it's much more affordable than the higher-end luxury hotels (Hyatts, Four Seasons, etc.). By contrast, we had drinks and dinner at the Sanur Hyatt and it was expensive (full American prices, $20 for fruit drinks and $70 for dinner). The Plaza's common spaces and our room were very clean. Staff was pleasant and helpful. Food at the hotel was fine, with several restaurants and bar areas, including poolside. Pool was very nice. Hotel has a spa. Beach is only a 5 min walk away.
There are a number of pleasant restaurants and bars in Sanur, both on the main Sanur street or in the adjoining big hotels. You can walk to them via street or along the beach, or take a a taxi for a dollar or two, there are drivers everywhere offering to drive you. (Check balieats for restaurant recommendations.) If you need western food, Dunkin Donuts and KFC are across the street, as is a nice jazz club, bakery, and restaurant (we had lunch there and it was good).
This hotel great for people-watching, very international: most high end hotels in Bali seem to get dominated by one type of tourist or another (mostly Australians, or mostly Japanese, or mostly local/Indonesian, etc.) but you see a big mix of people at the Plaza. The Plaza has become a place where well-off locals have their wedding parties, etc. so the lobby is always full of people coming and going.
The hotel is a very convenient location if you want to stay near the beach but you're also doing driving tours to the rest of the island. Almost all the island's tourist spots (Ubud, various temples, etc.) are north of Sanur / Denpasar / Jimbaran / Nusa Dua, and traffic is heavy and driving slow. From Sanur, Ubud is only 45 min away, so it's easy to go to Ubud just for the day. If you're down in the Nusa Dua area, it's a 45-min drive just to get to Sanur.
Overall, I would recommend this hotel, as long as the person was aware of the pros and cons. If somebody was only in Bali to do a beach vacation and wanted to pampered and never leave the hotel, then there are other hotels in Nusa Dua or Jimbaran Bay that would offer a better (if more expensive) experience.