FF 30th anniversary sale on Steam: Do I get it or no?

So my history of FFs that i've beaten are 1,2,4 (2D),7,13-2, Lightning returns, 14..? technically? and 15 and Tactics A2

Now the FF's i've played but never finished 3,5,6,9,10,13

FF's I've never played 8,10-2

Which FFs do I go for the most? I hear that the steam port for some FFs like 5 and 6 were crap and that the old versions are better but I don't have access to said old versions?