I have lost count of the number of iPad cases I have bought. Few have lasted more than a month in regular use until I bought a Logitech ultra-thin keyboard cover.
So what are the key things I want from an iPad case?
First, protection; the aluminium keyboard clicks magnetically to your iPad to create a combined unit which protects the delicate glass face.
Second, a decent usable keyboard, which is where many other cases have failed. The keys are too small or are reordered, making them difficult to use. But the Logitech ultra-thin gives you a good-size keyboard which is easy to use.
It has removed my need to carry a laptop for anything other than long journeys, which is a huge benefit.