It can be hit or miss. I think the Old Guardian needs aging. I really enjoyed the 2009 I drank earlier this year. I tried one of the 2011 releases and agree, it was a bit much. The others will be in the cellar for a year or two before I try them again.
I concur with the recommendation of the Big Foot barley wine, (Sierra Nevada) the first time I tried it was the 2011 this year and it was fantastic. I've got 2 in the cellar for kicks but they're ready now IMO.
Hog Heaven (Avery) is really great too...Though with a caveat. I drank one watching the world cup last year. It must have been fresh, it was like chewing on hop cones. The intensity took me off guard. It took me the entire football match to finish and by that time I was in love! I tried another one a year later and it was a completely different beer. The malt character was through the roof, that abrasive hoppiness was mostly gone and just lent a supporting hand.
flying dog has a barley wine that I tried at a tasting. Not one person in the room (10+ people) drank their sample. It was disgusting.
Sure, they're not for everyone, but nothing is. I say to keep trying them when you feel a bit of curiosity. They certainly are NOT all the same, there's a huge amount of diversity in interpretations of the style.
Me, I love barley wine!