I got this a week ago, and was happy at first, did a few dips and pullups and it seemed all good to go and safe. But then a few thing happened.
First my Girlfriend put it lower to try some dips, thought she had tightened it in the doorframe enough, but it came out from under her (she only weighs 60kg, half the advertised weight limit). The same thing happened to me the next day, making me land on a really bad knee from an accident I had, luckily I didn't hurt it too badly. This however is partially our own faults for not tightening it as much as it should be.
The real danger though is with the Dips extensions. As you see in the last two pictures of the advertisement, the seller is doing pullups from them. However what you don't see is how flimsily they are held in place. The slightest inward force unhinges them and causes you to fall to the ground. My girlfriend did this and managed to land on her tailbone and hurt her back. There is no way of locking them into place more securely and if the force isn't exerted in 90 degrees to the pull up bar they come undone. This is a major design flaw which I see as hazardous. Not to mention that the handles aren't even comfortable to hold on to. I don't know why the dip bars need to be moveable especially seeing as you can't adjust their position, there seems little or nothing to gain from this except for the potential hazard.
Also If your door frame isn't incredibly secure, the force of tightening this into place is so high it has the tendency to make some door frames crack as it is pushed apart.
All in all, this is a poorly designed and potentially dangerous product which can do damage to the structure of your door frame. As just a pull up bar it works fine, but your better off buying just a bar to do that job, and one that doesn't push your door frame apart.