I bought this remote a few weeks ago. While it worked at a short distance, I couldn't get it to work at a distance of more than 1-2 metres, making the remote pretty much useless.
I sent it back and was refunded without quibble (thank you Amazon). Since then I bought the official Canon remote, which only costs an extra £5 or so. It works perfectly well at distances exceeding 5 metres!
It may well be that I was simply unlucky to end up with a defective unit here (other reviews of this remote seemed pretty good, which is why I bought it in the first place). Still, for an extra fiver, I think it's a no brainer to save yourself some time and buy the official Canon remote which works like a treat.