Hi Leseven,
I've stayed at the Patong Resort, in both the garden and pavilion wing, on a number of occasions. It is my preferred hotel as it is right in the centre of the action. Not sure of the joiner fee situation as I normally have my own female with me so I never have had that problem.
Although the pavilion wing is more modern than the garden wing, I don't like to stay there, as it is high rise and I like to keep my feet on the ground. I have never felt that the garden wing was dingy and anyway the last time I stayed there there were modernising it.
Another good thing about the resort is that it has two full size pools which is a plus for me as I normally swim laps

for a couple of hours each day.
I have tried a number of the other hotels in Patong but I always regret staying in them as I prefer the big pools of the Patong Resort.
When I next return to patong I will again stay in the Patong Resort Garden Wing.