I guess I stand alone in here. Big Beatles fan, and even though I like Lennon and Harrison better, I still like Paul quite a bit. I think his first two solo albums were great (McCartney & Ram), but it's similar to the Harrison situation with All Things Must Pass - quite a bit of Beatles material and their façon de faire overrode these first albums (something Paul said influenced Flaming Pie a lot too, having just worked on the Anthology Beatles albums). After that, it was downhill for everybody, with only Lennon maintaining some of their past brilliance, at times. Harrison needed the Wilburys to really thrive afterwards.
Still, songs like Junk, Monkberry Moon Delight, Mull of Kintyre are pure delight to me. As for his contribution to the Beatles, I am too guilty of liking the John and George songs a lot better, and rare are the Paul songs to show up in my favorites. Helter Skelter and For No One being the exceptions. But again, the second-tier Beatles songs are full of good Paul songs - Blackbird, The Fool on the Hill, and many more...
That being said, the most under-appreciated post-Beatles work, and also by far the most interesting, is Harrison's Wonderwall Music, one of my favorite albums of all time, better than pretty much every Beatles albums IMO.
sorry first link was no good