The Mash Tun is another overrated piece of crud, it might not be the worst pub in Brighton but I don't know why it gets so busy for any reasons other than it's location. The Wagon and Horses opposite is far better.
I'm amazed only one person fleetingly mentioned The Seafield on New Church Road, walked in once and like a scene out of a Western, everybody stopped drinking stared at me and my mate which led to us walking straight back out. I thought I was the only one so I asked other people and similar...