Best Value Line Stage Tube Preamps?

Given they are all multi-input, multi-output, balanced line stage tube preamps, what are sonic benefits of a serious Rogue RP-7 or Prima Luna EVO 400 vs. the $899 Schiit Freya Plus? Currently these would feed a Parasound Halo A21 into Legacy Signature SEs, with all cables and speaker placement constant. I know the relevant mfrs/dealers all offer trial and/or return policies, but living far from any source and disliking return hassles, I'm soliciting expert opinions before (preferably, in lieu of) undertaking in-home experiments.
I know that much depends on one's own listening habits and sonic signature preferences, but surely differences in power supply, output impedances, etc. might be objective benefits to spending the 5x more coin for a bigger, badder device?
Check out "Space Tech Labs". They have many different components and can even build custom if you want. The owner will answer any and all questions you have, even give you recommendations.  Tube rolling is great because some of his preamps can take hundreds of different combinations. The one tube that make the biggest sonic difference in his design is the rectifier. Changing a single tube for rolling a totally different sound is nice. Another thing you notice with his design, he uses output tubes in his pre...el34 up to kt100. This give a big open sound. I run one of his balanced preamps into active ATC speakers. 
Active speakers not an option in my main system. Nor tube preamps in my secondary system. But I do get the idea, also why it could work for those otherwise situated. Very interesting about Space Tech. Need to read up on that, thanks.
Given that very helpful clarification, what would be your optimal components for a balanced line electronic chain (source - preamp - amp)?
Optimal? The sky is the limit...

I prefer analog, and since all cartridges are balanced sources, I would probably choose a Technics turntable with a custom plinth, equipped with a Triplanar tonearm...

Do you plan to replace the amplifier as well? 
Sorry about open-ended "optimal." I should have said "example."
And yes, on this prescription a different amp would be needed.
Such as .  .  .?
My favorite line stage over the last couple decades has been the Herron Audio. I consider it the best value in the higher price category. In the moderate to low price category Black Ice Audio, the new line of products by Jolida, offer tremendous value and are worth checking out.