The Bulldog was my local in terms of distance from where I lived at least, but I didn't get in there too often - not that I ever saw any trouble in there mind (Don Murray and the England prop Barry Nelmes who used to play for Cardiff used to get in there now and again). I've also been in most of the "dodgy" pubs in Cardiff named in this thread and always felt safe.
I spent a New Years Eve in the Foresters and would always go in there on a Canton pub crawl, got in most of the pubs with a reputation down the docks while I worked down there, used to be a regular in the Custom House on rugby international nights because it was one of the few pubs in town where you could get served quick and never had a problem in the Bridge - I saw more fights in the Corp, the Maltings and the pub opposite the Kings Castle that's name escapes me at the moment than I ever saw in those other pubs I've mentioned.
Never been in the Dusty Forge mind, so cannot comment on that. The one pub where I felt intimidated in was a place around the back of Neville Street where the place went silent as soon as me and a couple of my mates walked in and we soon agreed it should be a case of one, very quick, pint and then on to somewhere else - can't remember its name now.