Their is mainly three mobile os uses in smartphones. in which each os has different api and development environment . just compare here which os provides much direct ui tools and api. which has wide range of ui tools. I know we can create custom tools in each according to our need.
But which has wide range of stranded ui tools . and fulfill our requirements and what tools should be added in UI.
Trying to win the world.....................
SCJP 6.0 , SCWCD/OCPJWCD 5, BlackBerry Developer