I think the 55g RF87U is a very fun keyboard, and it provides such a bouncy and thocky feel, it's amazing! However, it's a bit fatiguing.
I also have a RF91U in JIS lay-out, which was initially variable. I enjoyed it, but I'm not a Dvorak typist. I have a weird typing style, but I just use QWERTY. Learned Colemak for a bit though. I think the 30g or 35g domes were too light for my liking, almost too mushy.
I now have a 45g uniform HHKB type-S and I think this is the best set-up for me. Although the 55g domes are fun to type on, this is the best for a long day of typing at the office. Not fatiguing, just the right amount of bounciness and thockiness.
However, again, it's purely subjective. Best of luck!