For me, this was a good purchase, clips on easily and feels secure and makes your controller look pretty cool. People are rating low because the buttons don't stick out as much with it on... not a problem at all, as you soon get used to it, and now it feels better, going back to a normal control feels horrible. Only minor issue, is it's a bit harder to take off to clean control e.t.c.
This product definatly looks good, clips on easily, and makes your controller stand out a little, HOWEVER because the plastic is quite chunky, the buttons are not so easy to reach, which becomes quite annoying after a while and you have big hands!!! For 2 quid you cant really complain, but if you play on your ps3 a lot, then i would look for something more user friendly :D