We have been using notification services as well.
And I agree on previous points about it.
In addition, I really suggest you to get some good book if you start working with it. I myself have Shyam Pather's 'Microsoft SQL Server 2005 Notification Services', it took me up to speed much faster than going through SDK samples myself. Also there is a lot of things mentioned which I never would have come up with otherwise. As previous poster mentioned, it really is not intuitive and requires you to know how things work with NS.
About debugging, yes it is difficult, and requires quite a bit of NS knowledge, but it is doable. As usual, better start with simple implementation and then add more things to it.