I have a beat-up 1970 Super Reverb with non-original speakers. I also have a 1965 Deluxe Reverb with the original speaker. I got the DR because sciatica doesn't let me use the SR all the time. I have been A/B'ing these a LOT lately and I have to say that the DR is not what I expected. I really like it - don't get me wrong - but it has way more treble than the SR (unless I use the bright switch). I have to put the treble on the DR at about 5 with my Strat whereas I have it all the way up on the SR with the same guitar. Also, the SR just has a ... twanginess that is missing in the DR. The SR also has a kind of "scooped out in the middle" sound that I like.
Now, I know that these descriptions are entirely subjective. It is just an overall impression, but has anyone else had a similar SR/DR experience?