I know that some of the "old school" purist photographers malign the use of remote controls but I haven't yet learned the art of sticking my head down a puffin's nest at the moment it is giving birth, whilst remaining invisible - so I swear by them.
In all seriousness, if you want to take decent photos, you should have some kind of remote control in your kit - and this one takes it a step further, allowing you to remotely view the camera's viewfinder via a handset.
I have been using Phottix gear for a few years now and I have always found it to be robust and reliable - and not too heavy on the batteries like some other remote controls.
It is expensive, I won't deny that - but it does what it says on the tin and it has a very usable range. I find it invaluable.