best power conditioners under 4k

I can hardly say what is "best," but I've owned a few brands over theyears (Furman, Shunyata, Isotek) and I am really happy with my recent purchase of Isotek pwer conditioners (Titan and EVO3 Sigma).  I bought these after hearing a demonstration by their sales representative.  The big change was between no conditioner and their relatively inexpensive powerstrip with built in conditioning.  The smaller improvement, at progressively higher price was still worth it to me, but, declining marginal utility is clearly at work here.  

An Isotek dealer in my area has a dedicated main power panel for the audio system function, including multiple isolated lines running into each demonstration room.  Even then, with a noise meter plugged into the power, there was plenty of noise on the line.  When the meter was plugged into the Isotek gear, there was either MUCH less noise or no detectable noise.  The audition of music also showed there was a substantial improvement in sound even if there was no actual "noise" that could be detected from the listening position without the conditioning--the sound seemed less artificial and more relaxed (without sounding dull or lifeless) and the soundstage more realistic (soloist seemed to be in a natural space rather than pasted to a spot).