I own both an IO (NOT a signature version) and a phono stage custom-built for me by Kevin Carter at K&K Audio. In my system, the K&K holds its own with the IO and bests a number of other phonostages to which I did comparisons (at 1/2 to 1/3 the cost in some cases). I am in the process of writing an overdue review of this phonostage which I plan to post within the next couple of days.
Aesthetix Rhea vs. Io Signature
Having read most of the posts re: the Aesthetix Io (both with and w/o signature and dual power supply upgrades), I think I understand its excellence, yet have not auditioned it. However, I'd like to keep things fairly simple from a heat/maintenance/no.of boxes/cost standpoint. Thus, my interest in the Rhea. Would those of you who have experience with the Rhea vs. the Io comment as to the distinctions. The concern I have is how much body, weight and richness of soundstage is sacrificed vs. the Io (let's assume with single power supply, signature version).