This is the second set I've had. I lost one of the first set down an airline business class seat!
I decided to upgrade to a higher model, my original ones being 5 years old. The difference was significant in that the sound is more natural. The cheaper ones operate in a range of 5 different frequencies which can be tuned individually whereas the more expensive ones I have now work on 20 different frequencies. Even the budget ones make a huge difference though.