Just arrived home today after 10 days at the Millennium, had no major problems except we ordered two single beds for the kids room and got a king size bed instead but the problem was fixed the next day.
Due to the mix up I can comment on both the Lakeside and Beachside rooms, as has been stated in other reviews the rooms don't have great views especially the lakeside (car park etc) , but if views were my number one priority I wouldn't have stayed in this hotel I would have booked the Diamond Cliff or the Novetel which both have great views of the water (we stayed at The Diamond Cliff in April 2012). However we chose the Millennium for its central position which is second to none and found the facilities to be excellent. Both sets of rooms we stayed in were presented in a clean and good condition, the staff were friendly and although some of the staffs English was limited we had no problem communicating (we are in a foreign country after all, if I wanted to hear good English I would of holidayed at home).
The breakfast buffet wasn't spectacular but was certainly adequate and up to expectation, the facilities including the pools and gym were excellent. The room windows and doors to the outside we're double glazed and kept most of he noise from Bangala Road etc out and would only disturb the lightest of sleepers.
I would recommend this hotel to anybody who wants to be in the heart of the action of Patong Beach and certainly would stay again if the occasion arose.