Synergistic Research Tesla Plex SE ac receptacle

Thanks Tonyptony.
I may eventually try a Maestro, but I'm going with a Furutech GTX-D eventually.
And I trust your experience, but I do need to point out that Neil Gader has also had these (although with a Powercell 10SE) and was quite impressed.
I do not doubt at all that the Maestro may be superior, just that it would be strange that the Tesla had an artificial quality in the upper mids/lower treble. How did it manifest - meaning what sounded "wrong"

Well, true to my own dictum to give it at least a year, now it's been 3. 
I've bee using the Furutech GTX-D ® for the past 2 1/1 years. Due to needing another dedicated outlet, I put in the Synergistic and had the electrician come over. After he finished, I  listened to the the music with just an integrated amp plugged in to the Teslaplex SE. While the sound was dynamic and exciting (and it had better low-level detail than the Furutech I lated installed), I have to agree that its upper midrange and treble are exaggerated (bright and edgy). Simply unplugging the power cord from the wall and plugging it in to a PS Audio Power Plant lessened the brightness, and this brightness persists, no matter what music was playing, unless it was say, Blood, Sweat and Tears, a pop CD with a slightly muted upper end, for which the Teslaplex SE compensated, providing a more "brilliant" upper midrange. But on Mercurys - and even RCAs made in Boston Symphony Hall, which is NEVER bright when hearing music in it - the sound is a bit edgy. An "Enjoy the Music" review of several years ago also found the Teslaplex to be "crisp" in the upper mids and treble.
My only problem with the Furutech is that it slightly masks low-level detail and while it has dynamics, it does not do it in "0-60mph". It sounds just a bit more slow off the mark, like 0-45. And I have two of them, so it's not sample-to-sample variation. I was surprised, but then, it may be that the Synergistic hypes the detail along with subtle information. I'll have to put in a Maestro or some other outlet to test that out. For now, just posting.

I think it's clear that the Synergistic Tesla Plex SE (not the original Tesla Plex) is a bit bright and glaring in the upper midrange. The other side of that is that it excavates voices in a way that no other outlet does - not even the Furutech, but this is what happens when a component is hyped, particularly in the lower treble: it makes voices breathy, so you can hear every exhalation, inhalation, hell, even if the singer is wearing a crinoline dress (they a rough fabric, so if the singer moves, you can hear the dress swish!) 
Back to the Tesla Plex SE. I have one installed in my PS Audio Power Plant and a Maestro in the new dedicated outlet in the wall. Just moving the power cord from the Maestro showed me that the Synergistic moved the singer closer to me. Along with that, and doing a lot of listening to 'The Best of Blood, Sweat and Tears (doing a lot of listening to that these days, along with the Byrds, Cream and other 60s groups), the lead singer's inflections are simple to hear and how he shapes the notes. Blood Sweat and Tears uses a BIG brass section, and brass shows brightness very easily. So, it's great, yet fatiguing at the same time. And I'm switching between Shunyata ZiTron power cords, PS Audio Statements and ESP power cords. The only cord that allows the brightness to be ameliorated using a Synergistic is the second generation Shunyata Python power cords, which were still  - in that generation (circa 2005-2006)  - sucked out a bit in the upper midrange and lower treble, so the Syngeristic outlet works in a complementary way. Still, there is the matter of grain: the Tesla Plex SE DOES have a bit of grain. I wonder why it is not as obvious in their Powercell line conditioner, but I suppose they've compensated for it. Besisdes, live music doesn't compensate in the way audio components do. Rarely have I heard brash sound (except when Carnegie has Pop Concerts, such as Nancy Wilson with the Count Basie band, and Carnegie uses those huge, Glassy-Sounding, BRIGHT speakers. Those things will shear your ears off, even from 2nd Tier seats. I dislike them intensely.

It's a struggle to enjoy the Maestro,  natural though it is, due to its not penetrating as much "into" the subtle vocal details in the throat (humming, for example) as the Tesla Plex,  so both male and female singers sound good, but not completely mesmerizing. If you listen to male and female voicals, you'll love the Tesla Plex. On the other hand, the Maestro has great bass weight and  dynamics (just FEEL the  drums knock your eyeballs out when they get going, classical, rock or jazz). The Maestro is very clean, but, due to being in row J or M of the orchestra in contrast to the Tesla Plex SE (row F ALL THE WAY!!!), the soundstage is ALWAYS a bit less exciting with the Maestro. Not all recordings are recessed, nor are they all, like the Tesla Plex SE, Row F. So, it's a tossup, except the Maestro being finer grained (aka "natural") the way 100 speed (the Maestro) film is compared to 400 speed film (The Tesla Plex with more apparent grain, especially evident on massed violins and brass more than any other instrument in an orchestra) - for those who remember film.
I agree completely with DavidPritchard's assessment. I've had Oyaides, PS Audio. Synergistic, Furutech GTX and SWO-XX, but not the new Furutech (nano-based) outlets.
Incidentally, PS Audios are a little bright in the upper midrange, but not the degree to the Teslas, but they don't have the clarity, transparency and punch of the Teslas. Nor do they excavate subtle voice inflections as well.
Well, that's all I got. Hope it helps others. And The Oyaide R-1 doe move the soundstage forward. Initially it sounds great, but then it sound a bit 'hi-fi.' Whew….I'm going to bed!