I spent a few days at Peninsula Paris this past spring and while it's an impressive property in many ways I had two major problems. First, the location. Like the Shangdi-La it's in the 16th but at the Shangri-La a few minutes walk down the Avenue President Wilson brings you to the Pont Alma to cross into the 7th or the Avenue Montaigne. The Peninsula is only convenient to the Arc de Triomphe and the Champs Ulysses and I found myself taking taxis far more often.
The second problem for me was that as beautiful as the rooms were, and they were beautiful, they could be in any city in the world. Totally luxury generic. I much prefer rooms that reflect the city I am in, such as GV, Shangri-La or Plaza Athenee.