For me, the HHKB Pro 2 experience is the unification of the 60% form factor, Prof. Wada's layout, Topre switches, beautiful PBT keycaps, and overall styling and design. If one thing dominates for me, it is the layout. I think if I were not going to use the Wada layout, I might seek the Topre experience through other keyboards, such as the Leopold FC660C or the RF87U.
Some projects on the back burner include building 60% keyboards with a HHKB layout but using Alps, Matias, or purple Zealio 65g switches. It will be interesting to find out if I like these combinations as well as the genuine HHKB Pro 2.