I've come across a lot of airspace avoiding apps and log books and have seen MemoryMap in action, it's very impressive but I've seen it turn pilots lazy and out of practice of the traditional method of flight planning.
The apps that help you avoid airspace have their obvious advantages, but I never liked the thought of carrying, setting up and using my Android device. After all, how reliable are these apps and their GPS equipment.
For hour building, I felt that I was going to rely on my lovely new tech too much and if it was taken away from me (CPL training) I'd loose confidence and struggle a bit. So for that reason, tablets and smart phones have no room in my flight bag.