1. Hinge is exposed if the door opens outwards. They use normal Full Mortise Hinges. That's the type which you find on most doors. If the hinge is on the inside, it is not too bad. But most back doors open outwards and thus expose the hinges. These can be jacked fairly easily, even if they are 'seal welded'. Fully concealed hinges are the best.
2. Many do not have an all round frame. Most of the cheaper doors have to top and two sides of the frame – like a normal door frame. This leaves a gap between the floor and the bottom of the door, especially if it is poorly installed. My friend experienced this problem. He now has to use a sweeper strip along the bottom to seal from outside dust etc. The main problem here is it creates a pry point.
3. There are a number of security doors that have built in ‘grills’ where we can open a small inner panel for ventilation. To be frank, I’ve looked through many designs and brands. Some have welded in grills etc. which are better but still not ideal. The inner panels are also very weak, especially their locking mechanisms - they can be easily pushed through/punched out with not too much force. If you want a grill, you’ll need a double layer door+grill system. Unfortunately most of these incorporate both into one panel severely reducing safety. If you want ventilation, open your windows
4. Check to see that the panel of the door is from a single sheet. Many use multiple pieces welded together to optimize material consumption. Single sheet hydraulically pressed panels are the best.
Hope this helps ya’ll select