I have just finished installing a Furman IT-Reference 15i into my system. Purchased 9-of-10 used for $1150. This is my first experience with power conditioning beyond the IsoMAX units. Observations:
(A) I think it's a real shame that all of eleven of the outlets are switched. In this day there are quite a few devices which like to be receive standby power when switched "off", and the two I happen to own (Cambridge 840c and Marantz NA7004) could not be connected to the Furman for this reason.
(B) There is no ramping of output on power-on: you will be sending significant transients through your gear when turning the unit on/off. In my installation it seems to take 30 or more seconds before I can turn on the power amp because of an unsettling 60Hz hum.
(C ) I initially connected my phono and line preamps to the "Symmetrical" (balanced?) outputs, and was really disturbed at the flatness and lack of life which I heard. Acting on a hunch I moved these devices over to the "linearly-filtered" outputs. The move cleared that up completely, a change which just amazed me. The symmetrical outputs remain unused.
(D) At the price I paid, and given the caveats above, I have to say I am -very- pleased with what the Furman has added to my system. Noise: way down, most interestingly in terms of the noise being picked up my my Shelter 501 II MM cartridge (overall hum AND induced TT motor noise seem to be gone). Everything seems to have gained as well in definition and presence (I am terrible at hifi adjectives). Overall, installing the IT-Reference 15i did a LOT for my system.