I haven't used it but I checked a couple of videos now, to see what it does. If it was free I would have tried it, just to play around, but considering that it's paid I don't think it is worth it in my case.
I normally work on advanced boards and speak to my PCB manufacturer to agree on a particular stack. They prepare the stack and send it to me, so I don't need to bother with that. This way it both saves my time and I no I have a proper stack, with well calculated impedance, etc. I am also sure that it will be manufactureable, since the manufacturer provides it.
If I need to make a very simple board, I use some of the simple, pre-defined layer stacks of the manufacturer (normally the cheap manufacturers have a few default stacks which can't be customised).
I don't think that the ability to import rules is that useful as well, since you need to know how to do this manually anyway, it doesn't save a lot of time and you have better control by doing it manually.
That is my personal opinion, it could be useful for some people