Yes, my RF87UB boards were worth it, at least to me. I have both the 45g and 55g models, and I like both of them. I have not tried the variable-weight RF, but I anticipate that I would not like it, because I believe that the 30g keys would be too light for me.
Among Topre-switch boards, I've tried the Leopold FC660C, RF87UB 45g and 55g, and HHKB Pro 2. My favorite form factor and layout is that of the HHKB Pro 2, but I find the sound and feel of the RF to be more refined. I like the sound and feel of the FC660C, but I didn't like the keycaps that were available at the time, and I prefer either the TKL form factor/layout of the RF87U or the form factor/layout of the HHKB.
I've also tried the CM Novatouch, which has hybrid Topre switches with stems compatible with Cherry mx keycaps. I liked it the least of the Topre-switch boards I've tried, but I think with the addition of silencing rings it would be a contender. Plus it has the added benefit of access to a universe of keycap colors, styles, and materials.
Currently, my daily driver is a black HHKB Pro 2 modded with 55g domes from an RF, silencing rings, and new Topre keycaps (blue alphas, blank black mods, red Esc, and red Fn). If I didn't like the 60% form factor and HHKB layout so much, I would be using an RF87U on a more regular basis.