For $500 you get a whole lot. I think the amp models sound very good, and I have an Fractal. I work in the business (I'm a Luthier), we get amazing deals on gear. I got a customers used Axe FX II & controller for an insane price that I just could not pass up. I would never pay $3k for it new.
I have a POD XT I use for direct recording. The HD500X was really a curiosity buy. I think it's is a huge leap forward and I've had just 5 hours with it.