Value of a preamp?

Would not touch any Limpazator products with a 10 foot pole. Nothing but problems. I am normally very impressed with EU gear. 
 

Depends on your DAC! If you get the new Lampizator Poseidon, it does not need a preamp, because the impedance level matches any amp. 
same with playback designs.

I don't understand the question.

For people going straight from their DAC to amplifier, you don't know what you're missing. It's been a huge difference for me in several iterations of my systems through the years.

@tonnesen - I only saw your comment now. Very nice system BTW. The Playback Designs player is unusual in using an analogue volume control, thus achieving volume reduction without throwing bits away. How it compares to a preamp of commensurate quality for your system could only be judged by listening - of course:))

@yoyoyaya 

Christiaan Punter has a nice piece on the value of preamps, even in a purely digital system, and a comparison of several preamps.  

@ddgtt Have you heard any of the Aries Cerat preamps, and any thoughts on how they compare to the Stern and the others you listed?