Well, first of all, anyone with wrist issues will find that gripping the handles immediately makes the Perfect Push more comfortable than floor push ups. But that's not really the big benefit. The biggest advantage of the rotating handles of the Perfect Push Up is that you can add internal rotation to the upward phase of the push up movement. Internal rotational gets the pectoralis muscles much more involved, and gives you a better overall workout.
Another benefit of using the handles is that you raise up off the floor slightly which allows for a deeper push up and a wider range of motion. A wider range means more muscle recruitment, and more involvement of the muscles of the arm, shoulder, and chest. Bottom line: this style of push up works the muscles a bit more thoroughly than the basic push up.
At about $30 for a set, they are a nice addition to your home equipment set up, as long as you use them regularly. One simple way to develop a push up habit is to leave the Perfect Push up somewhere you will see it at a time when it makes sense to use them. Keep them next to your bed, and you are more likely to get into a habit of doing a few push ups each morning when you get up or each evening before you go to bed. Putting them in the basement, or a closet, might mean that's where they stay. So make this little item a part of your daily routine.
There is also a smaller travel version of the Perfect Push up, but I'm not convinced they are much more useful than the standard set.
If you are interested in using this bit of equipment to the max, you can search Youtube to find the various ways you can use the Perfect Push Up. If you just want a quick preview, check this one: Perfect Push Up Chest Workout Demo.
Unlike other pull up bars, the Iron Gym doesn't need to be permanently attached to the door and there is no hardware to install. It attaches to the door frame using a counterpoint system, s you can put it up and take it down in seconds. I did have to add a bit more cushioning to the edges of the bar that lean against the door frame—the paint was wearing off the door jams—but otherwise it doesn't do much damage to the door frame.
Again, this item only helps you get into shape if you use it, so even though it comes down easily, I tend to leave mine up on my bedroom door frame so I'm more included to do pull ups on a regular basis.
I purchased the Iron Gym for about $30 at a local drugstore. You can get them online or, most likely, at your local sporting goods store or drugstore.