Australians are very much the most popular people in Wales (and probably Scotland and Ireland, maybe France...) at the moment since you knocked England out of the rugby world cup
If you can find the right pub with the right people then it's nice, unfortunately you don't know until you get there. We were just out of town for a couple of days and we went to one place that was pretty bad, too crowded, too loud and whatnot, so we went to another place instead, was so much better. Quiet, not crowded, cheap, had a pool table, darts, got talking to a few people who were really friendly.
I'm not a big drinker at all but it is nice to find somewhere like that you can go to.