Tabbed pane CP is not suitable for more component categories. More then one category tab rows make toolbar too wide. Tiny version of CP partially solves these limitation. It allows to shrink toolbar to one line. Is also well used with many categories and components.
Less accessibility is disadvantage of it.
Means that it takes two cliks and longer time to select usuall components. Toolbar mode means component palette displayed in main window toolbar and is expected to be used by users which use traditional set of components and have bigger screen resolution. Top compoennt mode means CP displayed in its own top component. Users which use more categories and components or have troubles with window arrangement due to small screen size should use top component style. Top component is NetBeans window system component, which could be docked into arbitrary window and is represented as one tab in window tabbed panes.