I would love to have an Apex controller. However I am not going to pay over $700 for one only to have to spend thousands more just for compatible items to work on it
I was kind of shocked to see the amount of people not using one.
Controllers make things easier, but are not a necessity for most. As some have indicated, frequent travel makes them more of a necessity.
That said, you shouldn't need to spend 'thousands more' for compatible equipment. You don't have to use the WAV powerheads and the COR pump; any power head will work fine, ditto with most other things. My advice is to buy equipment that is compatible when making purchases (i.e. when you get a pump, get a pump that has a 0-10V input). This applies to almost all controllers, not just Apex.
I purchased an Apex several months ago, and my experience is that while not necessary, it definitely makes life easier. After you have one, you also tend to find other uses for it.