markainsworth, I’ll give you my impressions here, hopefully not too boring for others. I was in your same exact position a few months ago except my budget was a couple of hundred dollars less than yours and Aric’s Unlimited caught my eye, prior to his latest modest price increase. It brought the much missing warmth to my system right out of the box. As noted, its a full tube design and with the exception of a small PCB board for the phone input RIAA the inside is all point to point wiring, very homemade looking. Its not a fancy piece at all and the case, power switch, and knobs, are all very basic but it sounds excellent. Aric is also a pleasure to deal with and gave a list of upgrades that he had tested extensively. I first upgraded all the tubes with what he recommended and the sound quality improved significantly. I then asked him about other upgrades and he suggested replacing the cathode follower capacitors and the specific values and brands. As a novice DIY guy, I took the plunge and changed the capacitors a couple of weeks ago. Fairly straightforward in a point to point circuit. I can tell you this modest looking preamp now sounds like a real high end preamp. I put it up against a friend’s Audio Research LS26 and we both could not believe how great the upgraded Unlimited sounded. It could not match the little tighter/lower bass of the LS26 but we both felt it had warmer midrange and nicer soundstage. Even the upper end drums and cymbals sounded more crisp and sparkly. We thought it was a little what people call more "tubey" but that was the sound I was after. The total cost of the upgrades was roughly $90 for the tubes and $60 for the capacitors.
As for the noise floor, it is completely dead silent, even the phone input, but it has a knob on the back to adjust the output gain to match the input sensitivity of your amplifier or even compensate if you have super high efficiency speakers.
Send me message or email me if you have any more questions and sorry about the long post.