I've been disappointed more often buying something that I heard in person. In two cases that spring to mind, I was in a hifi store just browsing around and heard something that caught my ear and seemed like a great deal. I didn't do any research, didn't read any reviews, just relied on what I heard with my own ears in the listening room. It wasn't until I got home and listened for a while that a particular shortcoming or another reared its ugly head.
Most of the time I make purchases with intent. That is to say that I'm looking for a particular piece that has certain sonic characteristics, and also has the right connectivity to work with the rest of my system. I do a lot of research, using both professional and user reviews here and and other places, being careful to "read between the lines". I'm almost always happy and satisfied with those purchases. In most cases, the professional and user reviews are based on extensive listening and tend to help me avoid characteristics that are not to my liking.
Most of the time I make purchases with intent. That is to say that I'm looking for a particular piece that has certain sonic characteristics, and also has the right connectivity to work with the rest of my system. I do a lot of research, using both professional and user reviews here and and other places, being careful to "read between the lines". I'm almost always happy and satisfied with those purchases. In most cases, the professional and user reviews are based on extensive listening and tend to help me avoid characteristics that are not to my liking.