Stayed at WHO in October 2011 and was very pleased. The location is not right next to the Louvre and Notre Dame, but that is definitely a pro since it is not a very touristy neighbourhood and restaurants nearby won't rip you off. It is within walking distance of Sacre Coeur and the Louvre and we even walked as far as the Eiffel Tower but that might be pushing it a bit. The metro is only a few blocks away, and it is quite close to Gare du Nord which is where the RER trains from CDG arrive. The hotel offers breakfast, but we found cheaper alternatives nearby with more citylife around them.
When arriving, we asked if they could recommend a restaurant in the neighbourhood and given a flyer to a place called Flo. Based on the flyer, it looked quite touristy, but was definitely not. It was a really enjoyable experience, good food and nice people. The flyer also gave 10% off the bill, so I really recommend it.
Only downside is that they charge for WiFi (10€) which is a bit greedy, but apart from that everything was really good.