Having done both T5 CCR and T3 Galleries First in the last month I found T3GF an equally good experience on the grounds of it being (admiteddly on a Friday morning circa 9am) virtually empty, very clean and with a friendly / attentive staff. CCR may have better food and viewing options from the terrace but if you're looking for somewhere pleasant to relax and have a drink before the flight then T3GF worked very well for me.