Some people get the mistaken impression that the "build quality" of the HHKB Pro 2 is not as good as that of the Realforce keyboards, because the HHKB Pro 2 uses case-mounted Topre switches, whereas Realforce uses steel plate-mounted switches. The Realforce sounds more solid and less hollow than the HHKB Pro 2 and the switches are less yielding. Some people prefer the sound and feel of the RF boards, but others prefer the sound and feel of the HHKB Pro 2.
The layout of the RF boards is standard. One selling point of the HHKB Pro 2 is its unique layout, which some people find intuitive and efficient, but others prefer a more standard layout.
The Novatouch has a standard TKL layout like a Realforce RF 87u keyboard.
To me, the Novatouch has a very light touch. My own preference ranking for sound, feel, and perceived quality among Topre-switch boards that I have actually tried is as follows:
RF 87u 55g > RF 87u 45g > Leopold FC660C > HHKB Pro 2 > Novatouch
For layout and form factor, I would rank the HHKB Pro 2 first.
The main attraction of the Novatouch for me is its compatibility with Cherry mx keycaps.