I second the vote for mono. I didn't think I would care for the mono because my introduction to this music was all in stereo. The stereo versions are fun and worth the novelty of hearing some interesting studio experimentation. After a while though, the unrealistic mix decisions begin to sound silly. Taxman from Revolver (Stereo), for example, has bass guitar, drums and lead guitar on the left, vocals are centered and then, on the right back-up vocals, a tambourine and injections of guitar solos. Vocals and instruments are all segregated. The mono version, in contrast, is a little more compressed sounding but instruments and vocals are together. In other words, it feels more like the band is performing the song together, in front of the listener, as one coherent unit. Both have their merits and everyone has their preferences. I'll take the mono. :)