Are the really pricey HT Pre Amps worth it?

Combining a prepro with a stereo amp that has by-pass seems a good way to go.  I used a Bryston SP3 and Parasound JC 2 BP, and my Ayre KX-5 Twenty also can do by-pass as well. 

auxinput, the Parasound JC 1, 2, and 3 stuff has been boxed waiting to be sold for several years, replaced by Ayre KX-5/20 and VX5/20.  I've always used HDMI input to the Bryston SP3.  So I really can't answer your question.  Based on Kal Rubinson's review, I suspect the SP3 is more than adequate for stereo and surround.

Currently I'm taking HDMI form an Ayre DX-5 DSD disc player to the SP3 with balanced front LR from the SP3 to an Ayre preamp for surround.  Balanced analog from the DX-5 goes directly to the KX-5 for stereo.  Most of my music listening, though, is Roon via Ethernet to an Ayre QX-5/20 endpoint, with balanced analog to the preamp.

db