Well, if you haven’t played it yet the very best turn-based Final Fantasy game is actually Final Fantasy Tactics, and I recommend the wide-screen War of the Lions update that came out for the Vita and other platforms a few years ago.
Though, that being said, the best “Final Fantasy Tactics” like game is actually Tactics Ogre. :)
To be clear, VII would be pretty far below IV and VI for me as well, but he only asked about VII and VIII! I don’t want anyone here believing IV and VI aren’t in my top 5 FF games.