Mark Chaplin and Mark Pearce: I played Muirfield with three of my friends (all visitors from the USA) in 2007 and based on that one experience, they were "not very friendly". I could give you the details, but it's not really worth it, so I will not. Maybe the folks there were having a bad day. The weather was awful. However, I will say that the shower stalls (rooms, really) were outstanding, absolutely the best I have encountered at any club anywhere, and much welcome after our cold, wet, morning round. I think it's wonderful that many others have, apparently, had a better experience than we did.
I did have a funny experience though. In spite of rain gear, we were soaked after the morning round. Only a couple of other groups on the course. A USA-ian in another group did not realize he had to change for lunch, and wanted to borrow my soaked wool pants to wear for dining (I'd brought a change with me). Crazy, but I said he could wear them. Fortunately, and a plus for Muirfield, the locker room attendant, if that's what they are called in Scotland, had a complete outfit the man could borrow and wear for dining.