Which Final Fantasy Titles Are Worth Re-Buying on Android?

I am currently considering purchasing some of the Final Fantasy titles that have been ported to Android. However, of all the titles are are part of the main series and available on Android, I already own them on other consoles/platforms.

• Final Fantasy I & II: Dawn of Souls - Gameboy Advance
• Final Fantasy III - Playstation Portable
• Final Fantasy IV: The Complete Collection - Playstation Portable
• Final Fantasy V - Gameboy Advance
• Final Fantasy VI - Gameboy Advance
• Final Fantasy Tactics: War of the Lions - Playstation Portable

If you own them already, don't buy them, since they offer nothing new, aside from a graphical update for V and VI. Out of all of these you mentioned the only one that you should think of buying is FFIV since it is based off the vastly superior DS remake.

6 is probably worth buying for the sake of seeing that graphical "upgrade". Some of it looks good, though a lot looks quite terrible.