I have a pair of moderately priced Sony BT headphones. Could be a similar model given the price range.
You can't charge and listen at the same time (wtf)
I get no warning when the battery is about to die (combined with the above this really sucks, they shut off in the middle of something)
I dual boot OSX and Windows on my laptop and I have to re-pair the headphones every time I switch OSes. I suspect each OS has a different encryption key, but the headphones can't tell the difference between which OS is running.
They cut out and skip all the time when walking through the City. They are borderline unusable when walking between the train station and my office.
They cut out and skip occasionally when not walking through the City, for no discernable reason.
They have an obnoxious and unnecessary blue LED that blinks periodically when they are turned on. This lights up our whole bedroom at night and annoys the crap out of my wife. I have to keep a piece of black electrical tape over the LED.
These are the best bluetooth headphones I have ever owned, they sound great, and I absolutely hate them.