Your most disappointing purchase or audition?

Magico S3. It was in a dedicated room with McIntosh gear. It was OK, but not worth the money or the hype. No passion to the sound.

say the Pass Labs X 250.5. I used it in single ended mode, which I was told later was not optimum, although I never read that in all of my pre-purchase research. I bought it and auditioned it with 5 different speakers in my system, and in each case, the sound was thin and electronic. It was a really shocking disappointment.

Here are some units listed which are absolutely the opposite from sound quality what is written in their "reviews".
The golden rule is, EVERY unit gets a positive review, be it awful sounding or good sounding. The vocabulary will be the same (and is identical). Blind buy is really dangerous, the majority is really down at the docks....

When I did own Pass units I was sitting in a Demo listening to the latest Pass amps, at that time it was the "X" series and it was exactly as described. Ultra boring for me, so unbelievable dead that I could not believe that the same guy made the outstanding Aleph amps. Anyway, left side was a Pass Fan and he asked me what I think about those super-duper-reviewed amps, I lied and said "amazing". He loved me from one second to the next, smiled and told me his impressions about the "super soundstage", the "holographic detail" and so on and that they are M-U-C-H better than the model before (which I also knew very well). When I listened his explanations I really was interested to know what he did smoke that made him speaking about abilities which were simply not present. I mean, I was right beside him.

You see, there is a Fangroup for everything out there.

Syntax,
I learned a lesson from my experience with the Pass X 250.5. I bought it mainly because of all the positive professional and user reviews that I read. Since then, if I am unable to listen to a speaker or component before buying it, which is almost always, I rely more on Audiogon members whose tastes are close to mine in the components they own, and the type of sound they describe as their preference. It has worked out better for me.
Earlier in this thread for instance, one member said that he really disliked the Coincident Total Eclipse. I never owned them, but I really like them. I respect his opinion and preference, but realize that we have different priorities in sound reproduction. There are other members who like many of the same things that I do, so I put more weight on their recommendations.

Another vote for MF.

Back in the day, HiFi Heretic magazine listed the Music Fidelity B1 integrated amp as one of the 10 best buys in Audio along with the B&K ST140, Spica TC50s and I forget what else. Was lucky enough to find a B1 with an owners manual so I snapped it up. Wanted to run from the room every time it was on. Mated up to ProAc Studio 1's which I believe were also on the 10 best list too.

My most disappointing purchase was a Threshold S-200 way back when I first discovered this whole high end biz. I purchased it based on the performance of the SA-1's which were quite a different beast. It wasn't a bad sounding amp it just looked better than the NAD I liked as much during the audition period but was assured by the salesman that the Threshold was definitely better and twice the price. In any case I kept it for a few years before realizing that I just wasn't involved with the music. Sold it overseas to some guy in Norway for what I paid, he loved it.

I hear you Marty on the early ML Sequels, horrible integration of the drivers. I couldn't imagine who would purchase those speakers until I saw a guy lay down the green at my local dealer. I wasn't too fond of the CLS either for that matter but at least no integration issues. ML has come a long way since those early days.