For any car with an MAF, I stick with paper. The filter oil can leave a film on the MAF wires over time, as it's very easy to accidently over-oil when you clean the filter. The MAF can be cleaned periodically to correct this, but I prefer to just avoid the issue and use paper.
For a carbed application, this problem does not exist. Paper will filter better, as shown by lower silicon (dirt) content in UOAs (used oil analysis), but the difference isn't critical. There is no huge power gain by using a K&N-type either though. Having said that, I do have the K&N on my '71 for now, but not on my EFI cars.
1971 Nova SS-350 | 1998 Camaro Z28