They say that choosing one should be easy, but then they make you take a bunch of tests to determine what you should go for. And those are not easy. Plus they cost money, and take time.
I recently had to take said tests, and it took me over two hours to get them done. There was a series of online tests, and then two written ones. One of those you had to print off.
And if you don't finish in one sitting, you have to pay for it all over again.
The results give you a list of things you can try, but you still have to pick one and hope it works for you. At least once you go with one, declaring it is easy. Takes a lot less time too.