At $500, it costs far more than it's worth to me. YMMV.
That's more than twice the cost of a new B3n. That doesn't have a loop, but it has all the drives and amp / cab sims that make one unnecessary (to me). Again, YMMV.
The coming-soon Pod Go has even more to offer, including an FX loop, amp-out, headphone out, USB audio interface, etc. And all the sorts of drives and amp sims that the Plethora doesn't. And that's cheaper than $500 too.
And if you don't like the Pod Go because you want something to integrate with an existing board, you have the HX Effects and HX Stomp. They're over $500, but I think the HX beats TC in every category except for octaves. The Plethora looks a little smaller and is a decent chunk cheaper, so maybe...
I don't know. To me, $500 seems to be asking too much for what it gives you. It looks cool, but a feature and price comparison with other products on the market leaves me a bit underwhelmed overall, and just kinda wondering where it really fits in. It seems like it can't compete with the B3n on price or the HX / Pod Go on features.