No. The feel is actually quite different. In my experience, the RF 45g felt significantly lighter than the HHKB. Probably because the lack of a plate on the HHKB softened the landing and absorbed more of the force of the keystroke. Kind of psychological, but definitely noticeable.
And the HHKB is quite a bit louder than the RF 45g. Also probably because it lacks a plate. As far as money goes, I think asking if it's a waste is not going to be very productive, as most of us here already spend way too much on keyboards.