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?