Disappointments

I can honestly say "no". The only time I felt I took a risk was with my Acoustat 1+1s. The room I was going to put them in was too short heightwise. So I cut the ceiling drywall between the floor joists above to form a "trough" in the ceiling. I then finished the edges with wood trim and resprayed the popcorn. Looked like it was a deliberate feature. Talk about your "room treatments". 

They sounded pretty good but it wasn’t until I added an RH Labs sub that they really took off. 

Happy listening.

Well, not so much showroom gear... but the places I deal with over sixty years, are better than I am at system design and give me the right to return non-performing stuff.  They know my standard is to hear a positive difference right away.  And generally, they sell systems at $250K and up.  That said, I've bought some stuff, usually unheard, like some cables and power cords, that left me feeling flat when put in use.  Never heard a difference with fuses either. 

@elliottbnewcombjr No seat belts back then.

And to keep this on topic the Flame Linear was a was a total letdown and meltdown.

I will not buy gear without a home trial unless it is fairly easy to ship and return or inexpensive. The room is half the sound.

The room is almost irrelevant when you do near field listening. That's how you test equipment to begin with. You eliminate the room. And if it sounds good then you add the room. Clean wall current delivery is half the sound, and few of us have it these days.

To answer the question. No, no disappointments, I read before buying and before listening, if I can audition it at all. Usually not, I buy mostly used and will not exploit dealers.