There is no difference between the digi and the classic 'Cano except that you are more able to discern the exact temp that you are vaping at. Once you find the best temps that work for you with the classic, you are golden.
I've never had much experience with the easy valve, but I believe the basic difference there is that the bags come mounted on that one, and you have to attach your own on the solid valve. There is a bit of a learning curve to attaching the bags on the solid valve, but once you've changed the bag a few times the tricks become self apparant and it only takes me about 5 minutes to complete the change now days.
I've used the classic for about 3 years now and introduced it to many other's, a few of those folks went right out and got thier own. Once you've used it, you realize how beneficial it can be. It saves you alot of medicine by being so efficient, and it gets you higher (medicates better). Hope you enjoy yours as much as I've enjoyed mine.
Peace...j.b.