I bought this along with the Kensington anchor point despite the bad reviews.
I agree with some of them stating that the Kensington anchor point has a rubbish plastic cover which allows the potential theif access to the screws. I think that this is easily overcome by making a visit to a DIY shop and purchasing irremovable screws (once the are screwed in, you cant take them out again so think carefully about where you place it). For a determined thief they probably wont bother the hangaround and unscrew the screws anyway, they will simply take a pair of wirecutters and cut the cable. I do not think that this will stop the theft of your laptop if someone REALLY wants to pinch it, but it will stop the opportunist, and they will be more likely to pinch another laptop form another unsuspecting victim. In reality, walking around with your laptop in a laptop bag will attract more unwanted attention and you are proably more likely to lose it that way with a simple 'snatch, grab and run' technique.
The lock itself is probably as good as you can find, and the cable it tidy and a little qwerky - if you are lucky enough to have a purpose-built table with a hole, or using one in public, such as a library, then don't bother with the anchor point.