Another positive report from the Delta here. As a Plat I've always been upgraded from the most basic room to an Exec level room with a Castle Park view, couple of mini bottles of wine at checkin. Lounge is fine with drinks and bites from 5.30 to 7.30 (8.30 for alcohol). Breakfast is in the main restaurant and is a big spread with all the usuals and a bigger range of cold cuts and fruit than most similar hotels (for comparison, the breakfast here is miles better than the Marriott Cardiff which is a very limited buffet in the lounge). Service has always been friendly. The Marriott Royal has more character and might be better located depending on your need to be in the city, but given that I've just booked again for a Friday night in September and the cheapest room in the Marriott Royal is £194 and the cheapest room in the Delta is £86, I'll take the hundred quid and walk a bit further to the theatre...