For my master's thesis I had to evaluate GUI Libraries for J2ME (CLDC + MIDP). Because putting that evaluation in my thesis would be an overkill, I post it here, to make the evaluation for others easier.
Note: This evaluation does not claim to cover every criteria. I list some arguments that - I think - give a good impression of the different libraries. Of course, if a library had a property, which made it impossible for me to use (like if it was not free) I stopped investigating further properties. I hope this table will help some of you to see the differences, advantages and disadvantages between the different GUI libraries of J2ME, furthermore this list is a good starting point to start your own evaluation.
If you know some other libraries or have some additional information to the individual libraries, that you'd like to share, write a comment.
Very powerful and really an eye-candy. Looks very sophisticated and gives your application the IPhone-Look. Check the demo of this twitter-client, to see how powerful it is. Unfortunately it's not free.
Very sophisticated. Is not only a library, but a whole development-framework. Allows to deploy different variants of applications for different mobile phones or different customers. Has built-in features like auto-completion of textfields. Possibility to seperate application logic and design through CSS-like layout. Plugins for Netbeans and Eclipse. Has ListLayout, TabLayout, GridLayout and TreeLayout.
Some very clean components like checkboxes etc. but seems to support only normal alignment. no fancy containers like table-containers. Furthermore, there is no native use of the cell-phone textentry, only upper-case textfields without numbers for textentry.
Demo-Applications were quite confusing in the emulator. Some weird behaviour (command-keys didn't work) and navigation via 2,4,6,8 instead of direction-keys. (Felix in the comments added, that the direction keys DO work.)