I did think it sounded too crazy to actually do, but I really like the way it turned out (did you try our demo slider?). And it is just a single slider, so not as bad as multiple decisions, exactly. Admittedly it's harder than "monthly vs yearly" though.

In any case, I won't be surprised if you're right and it only makes sense if your users are nerds who will like it for it's own sake. :)

But there's a slider!

Slightly more seriously: for us, the premium plans are directed more to the hardcore users who are already committed and love the service, so more choice is maybe less daunting?