How about by the numbers? "I Started A Joke" peaked at #6 1969, and spent 11 weeks on the charts. "Alone Again" made it all the way to #1 in 1972, and spent 18 weeks on the charts. Plus, it's 38 seconds longer.
And at least the Bee Gees made up for it a bit with some groovy dance tunes later on. GilbertO'Sullivan? He follwed with Claire, then Get Down and disappeared in a few blinks.
Yeah, I's saying Alone Again is worse. Of course, I do have them both.