Definitely Diafine. Cheap to begin with, you could reuse it forever, it gives great results on all non-T grained films, with several added bonuses: speed increase, compensating development, not too high contrast. You also save money on the stop bath, not needed with Diafine
😉 However, it's not great with T-type films, nor when you deal with low contrast scenes - but in that case you can rate film at lower ISO and get contrast higher up again if so you wish.
Overall a winner IMHO
😀
Ilford Pan F rated at 80, MP, Leica 1.4/75
Tri-X rated at 1000 ~, MP, Leica 2/90
Ilford FP4 rated at 200, MP, Leica 2/35
Plus-X rated at 200, MP, Leica 1.4/75
Tri-X rated at 1000 ~, MP, Leica 2/35
I have some more tests in Fujifilm Neopan 100 SS coming up too, negatives look very very good, but I haven't scanned them yet.