You do realize that the combination of "What's the best 120 film" with "in your opinion" will lead to this thread listing every single 120 film in current production and a few discontinued with at least one person saying "define best" and another "depends on the developer" leading you to start another thread titled "What's the best 120 film/developer combination" that you'll combine with "in your opinion" leading you to, well, you know, right?
So I'll play anyway:
1. Strictly working with FP4+ these days, but have tried, and liked, Tri-X, Foma 100 and 400, Delta 100 and 400, T-Max 100 and 400... depending on the developer I used (sorry...)
2. Really like Kodak Ektar 100, hate the washed-out, overexposed Portra look that everybody seems to be going after these days.
3. Every film is odd.