My response is whether your desire is for long-term success online or not. If you aren't or "it's just a hobby", it may honestly not be worth the value, though even if it is just a hobby, imagine being able to eventually earn enough from a hobby that you can quit your day job.
Is it a guarantee you'll get enough value from a pro membership? No - of course not. Yet I only wish I'd joined all those years ago back when it was "just a couple sites" that I wanted to get better results from. Because in my case, that couple of sites effort grew into an amazing career.
So what it comes down to is how passionate you are to see success from your efforts, whatever scale they're on. And the more passion and/or the bigger the goal, the more valuable this place can be.
Heck - if you were to add up the hourly rate some of us in the Q&A area charge for the same kinds of answers we provide here, you'd likely find you're getting thousands of dollars worth of guidance for pennies on the dollar. (Admittedly lately I'm only answering questions here once in a while due to current workload, however there are plenty of great professionals who participate).
Throw in the ability to make use of some of best data evaluation tools in the industry (I get more value from Moz tools than from any other "similar" product) and it really can be a gold mine of value.
(posted by Alan Bleiweiss - Click2Rank's Search Director)