My experience with 80/20 vs. PB with several guitars is that the 80/20's are brighter (more treble, less low midrange and base). I switched to PB many years ago when I got a '96 Taylor 612c. As most folks know maple guitars tend to be on the bright side - the PB strings (D'Addario EJ 16's and later coated EXP PBs helped tame that somewhat. Not all PB (or 80/20) strings are the same, however, as most of us are well aware. When I got my RT in 2008, it came with Elixir PB nanowebs. I put a set of EXP PBs on it and immediately noticed a difference in tone (more trebly, less midrange and base and less warmth). I went back to the Elixir PBs. That guitar just sounds better to me with those strings. I then put the Elixirs on my 612c and noticed an improvement (to me) in its tone - more balanced, better midrange and base.
Obviously we all have different preferences for tone in any given guitar, and strings can make a significant difference in the tone of any acoustic guitar, probably more than all the other "mods" that can be made (changing saddle/nut or bridge pin materials).
I once read a quote from Brian Swerdfeger in Wood and Steel about investing $70 in a great education - buy half a dozen different kinds of strings and see what you like the best on your guitar. Sounds to me like a worthwhile investment and good learning experience.
Bill