1 or 3.
They both have a handful of my all-time favorites. About the same amount even. Both are ways above 4 for me in any case, and I never had 2. Not planning on ever getting 5 because there hasn’t been a single thing that looks interesting to me. PSP had the same problem, and I never got that either. Vita I do have, but it’s a non-factor as my library for it tallies up to a total of two games.
So 1 or 3, and I’ll vote for PS1, because my favorites there rank just a bit higher on average than those from 3.