Watch out for the ones on Amazon – the reviews are often by people who ‘received the item in return for an honest review’.
The ones I got for my birthday last year (which I had identified as being the best based on reviews) were utter gash and went straight back.
And Molgrips – on a very quick look, it suggests that the headphones you linked to have been reviewed by one of those reviewers – the first reviewer has a whole load of cheap items in his reviews including several iPhone cases as well as at least two Bluetooth headphone sets (and a vibrating cock ring too LOL).