Which is ~£80 if I remember rightly? To be fair to David, guys, that's pretty expensive for a bunch of PHP scripts.
I've looked at the 3.6.9 bug fixes and feature list; IMO it's not worth the hassle of upgrading to it. It doesn't really offer any world-changing improvements and it'll be a pain to set up.
I say stick with what we have unless you're really prepared to cough up ~£80.