I'd choose the Delos Vaugirard, good location, rooms recently decorated, good clients review on trip advisor. Single standard rooms are tiny, which is usual in Paris and in many European cities, for larger rooms you have to book a superior one. Staying 5 nights I think you'll only come to the hotel to have a shower and sleep. Clients review say that beds are comfortable and that you don't listen any disturbing noise from your room. If receptionist are not always nice it's maybe because the working conditions in the hotel area in France are really really bad.
The 15th district is nice, there are many restaurants and bars. There's s good Italian restaurant not far from the hotel, "Croccante" at 138, rue de Vaugirard, tube station Falguière. Delicious home made pasta, inexpensive.