Going for the One is the best because, musically, it's a lot more accessible than Relayer or Tales or even Close to the Edge without losing much of the depth those albums had, and it's more ambitious than Fragile or The Yes Album. Lyrically, Anderon's still sounding poetic, but not as dependent on experiences with hallucinogenic drugs. Anderson's lyrics have always been a little too "out there" for me, and later in the Yes discography they'd become painfully cliche. But Going for the One was his happy medium. It's only too bad that he couldn't maintain that level of lyricism afterwards.
To be honest, Relayer and Tales don't do that much for me, and, honestly, I'm not even that big on Fragile. Tales is just too long, with the good parts too far and few between. Relayer pulls everything back in, but while there's great parts like Soon, once again the long songs just seem to go on for too long. And Fragile just fails to sound like a cohesive "full band" effort. It really sounds like a very, very good demo stretched into a full album. If I had to pick my "holy trilogy" of Yes albums, it'd doubtless be (chronologically speaking) The Yes Album, Close to the Edge, and Going for the One.