They are the same class devices. None of them will work for transcoding video. Both of them will work like home network storage (files, photo, video, backup).
• 220j :
+ support much more apps included (not all of them will work due to weak hw)
- price 180+tx
- 512MB RAM
? VPN server
• F2-210:
+ 1GB RAM
+ price 120 tax in
- has the only basic set of apps (40+)
- no VPN server
Just compare the set of the apps they offer and you plan to use (to sync photos/files)