Two different Mobile based library

Hi, all,
I am developing an mobile based map application, and found that there exists many different mobile based map libraries. Attracted me most are the J2MEMAP library and the cloudmade mobile library. Could anyone tell me the difference between the two libraries? such as the disadvantages and advantages, the issule related to the license, and so on. Any advice is highly appreciated! Thanks in advance.
Regards.
tao