hmm - I'd say that the majority of American beer is over-rated, not under-rated. There are exceptions, but they're few and far between. Same goes for most of the European Lagers. Most of it barely qualifies as beer in my book - more like stale donkey pee with added gas... 
Nothing comes close to a good Old English Ale served straight from the barrel at the right temperature (i.e. not too cold). Old Tom, from preference...
Nothing comes close to a good Old English Ale served straight from the barrel at the right temperature (i.e. not too cold). Old Tom, from preference...