It's going pretty well actually. I originally had three different plans with feature-walls, but I hated doing that, so I just freed it all up under one umbrella. Stripe dashboard tells me the average subscription is around what Disqus charges ($9), so I think it's a good idea overall. I definitely recommend it. In my mind, if I see a product using a similar pricing, I feel more valued because I'm given a choice. But that's just me.

I do have a custom option for enterprises because their needs are always unique. I usually charge much higher for this (also comes with a much larger pageview count monthly).