It's a excellent software for managing things to do, and I pay monthly for it. It is very efficient to use, works offline and on mobile seamlessly, use a JSON format for storage, and can export in a standard format to avoid locking (even on the free plan).
I use it to manage things to do, listing, etc., but I would not use it for taking notes, IMO. The format doesn't look great for it.
Anyway, the free plan is good enough to try it on, and the customer support excellent.
I hope it will never be bought by some giant.