I've been developing for mobile for nearly ten years and trust me when I say unless you need to support a particular device avoid the legacy platforms, at least until you have a proven mass market app.
J2ME is Micro Edition for a reason, much of the seemingly simple on other platforms you will have to roll yourself and test everywhere.
BB dev is like swimming through treacle or as one of my colleagues put it "death by a thousand paper cuts without the relief of death at the end".
WebOS is a pleasure for web developers, but when you try and make custom UIs or deviate from the framework it can become a pain quickly
J2ME is Micro Edition for a reason, much of the seemingly simple on other platforms you will have to roll yourself and test everywhere.
BB dev is like swimming through treacle or as one of my colleagues put it "death by a thousand paper cuts without the relief of death at the end".
WebOS is a pleasure for web developers, but when you try and make custom UIs or deviate from the framework it can become a pain quickly
Symbian is thankfully a footnote now