I have stayed at the Plaza Athenee, Bristol, George V and the Le Grand. By far the best is the George V -- the Bristol is improving, and the Plaza Ath was the most disappointing. It seems at Dorchester Hotel Group properties, unless one is a regular and/or high roller your treatment is poor.
Le Grand, however, is a very good alternative as I feel they really try their best to improve and offer a great product at a more reasonable price compared to other top end Paris properties. If you can get a view of the Opera from your room, it is worth it. The location is excellent and Cafe de la Paix is also much better than it used to be in terms of decor and food quality.
However, having views of the Eiffel Tower from a suite at the George V is simply magical.