Me too! Do you draw on the screen or use a tablet with it? lol
As for the cell phone thing this is something that really intrigues me because I'm all about mobility (Who doesn't wanna draw wherever they go!). I've seen a few artist doing it... but never figure out what kind of phone they have lol
As for the main question, I'd say it depends on what you are doing... If you are use to using a tablet it might be a good idea to buy one as a back up because the cell phone thing might not work for you. You might get the phone and realize about half way through that maybe it doesn't do all the tricks you want it to. But that's just my thoughts