I've had two K&N's on our 60, here are my thoughts:
each time I installed the K&N, I replaced a filthy stock filter. of course there was a performance gain, but I suspect a clean paper element would have helped too!
When I switched from K&N to paper, I got a big gain. Again, the K&N was very dirty, the new filter clean. Go figure.
I'm running K&N now because paper elements are hard to get here- most 60's here run the 3rd world style filter housing, I've got the US style housing... so the K&N saves me hassle of looking for paper elements.
I don't really think that the K&N is better, and I miss being able to blow out the paper filter... I haven't had to clean and re-oil the K&N yet, that'll be an adventure as I'm sure nobody here carries the supplies.
For a DD, the K&N is probably great. You can ignore it for a long time.
For a wheeler, I like the paper as you can see when it is clogged up.
For an expedition style rig, I like the idea of having a spare paper filter on hand, but it doesn't really matter if there is a K&N or a paper in the housing.
Just my 2 colones (not many pennies, I'm afraid)