I have used PocketFMS for a few years and I agree that the interface is quite confusing but it has lots and lots of features.
I learned it by getting it connected to Microsoft Flight Sim (there is an output but it is quite tricky to get working) and had it on my laptop while I flew various flights on the sim. I then got to practice loads of different scenarios.
I use it on a tablet pc with a touch screen. It was hopeless on a pocket pc. Way too small and slow but on thr tablet it is pretty damn good.
I have tried Sky Demon. I am just waiting for them to release the rumoured PC version. The current pc version is only for planning but does not have gps. It is certainly more graphically pleasing that PFMS but I am not sure how it will live up to the feature set of PFMS.