User blog comment:Ghostwolf18/SAS 3 or 4 mobile?/@comment-25862085-20150404002729

Hmm, well they are both free, but as said you get a buddy to help you in SAS 3, but all the new things in SAS 4 are starting to get into mobile...

Its your choice, for lag reasons I'd go with 3, but whatever works for you.