I have tried a few conditions now, with different amplifiers. I can say with absolute conviction, they all add some sort of change to the tone of the system. There is definitely a synergy to what type of amp you are using and what you are trying to do. For example the Furman just added a haze to everything. It got rid of hum in my amps, but the Furman itself hummed. I did not like it much. A Topaz line isolation transformer in my basement was very nice with my CJ Premier 140 amp. Very little haze, but decent isolation from line noise. The Topaz line Isolation transformer made a mechanical 60 hertz buzz through my 811A tube based amps. The 811A just sound best in the wall as they don't hum much even with dirty power. I did not have the Isotec to test the difference. My preamps, music servers etc sounded weird through he Topaz, so I went direct to the wall with them. The Isotec Syncro sounded best on the SS Rega Osiris as stated above. It actually made that amp better all around. It added too much cloud to the CJ. It also made my stand alone preamps etc sound a little off. Better sound stage, but I did not like someting else I cant really say what, but something I did not like, so direct to the wall went the front end equipment instead of through the syncro.
I am a master Electrician in Seattle WA so I have been involved lately with installing updated power to peoples audio racks. I have heard the Isotec Equipment with Genesis amps. They work very well at keeping the Toroid coils from humming, but add a little haze. Not a lot, but with $100K speakers and $50K in amps, people want clarity, not cloud. If you can go direct to the wall, it always sounds better. From what I have heard. Adding #10 THWN wire on a dedicated feed to Porter Port or better receptacles is a huge step in power, ease, dynamics with every system. It is such an under appreciated upgrade, but only cost $1000 or so for a huge upgrade in performance. HUGE, as in really makes a positive difference. It does nothing to get rid of line induced noise from your utility. It does a whole lot to get rid of ground loops. Provided it is installed correctly.
In summation, it you don't really need a conditioner, don't get one. Get better power for sure. Get rid of all cheap light dimmers in your house and only use Lutron Maestro 600 or 1000 dimmers. Do not use the low power selector switch on your under counter lights. Turn them on high and use the Lutron to dim them. That will rid a ton of pollution you are adding in your house. Also, consider a Surge Protection device at your panel. Not at your rack. It won't do a lot to clean power, but it may save your system from some utility spike or lightning strike.
If you have specific question about your system, you can look up Kingrex under members and send me a private question.