I purchased this lock and took it on a cruise to secure my MBP while away from my cabin. It did what it was supposed to do without much of a problem. I gave it four stars only because, I found it a little awkward to attach the lock the first couple of days. It was a breeze by day four.
When not attached to the computer the lock appears to be flimsy, but that is not the case once it is inserted correctly into the slot on the computer and actually locked.
It probably will scratch the finish on your computer, if you do not take the time to align the t-bar locking mechanisms. They should be parallel before inserting into the slot.