This appears to be an original HP product. It powers my Compaq Prisario V5000 perfectly and even came with a new powerlead and UK plug. It was well packed in a strong plain brown box.
I bought a 'brand new' charger from here and within four months of purchase it had completely broken!! Unreliable products as far as my experience has shown! However, on a positive note my product was delivered within 2 days of purchase even though it said upto 14 days.
My old laptop charger had a really bad connection, so my laptop wasn't charging (obvs), and I was actually starting to worry that it might have been an internal issue with the charger socket or something, but I ordered the new charger anyways, it was only like £15, and thankfully it works a treat = a very happy customer =]