Personally, the HHKB is the best typing experience I've ever had. However, I tend to use the 87u's more frequently due to my heavy use of Visual Studio.
If you need easy access to arrow keys and the ins/del/home/end/pgup/pgdn cluster, then the 87U will probably be a better choice. If you want portability, go with the HHKB. The HHKB is actually louder than the RF, since there's no metal plate to dampen the vibrations, but it's a very very satisfying thock.
I have the standard RF 87u 45g, not the EK edition, but I wish I had gotten the EK edition (Red LEDs, yummy). IMO, you can't go wrong either way. It just depends if you want to take the time to learn the HHKB layout.