I have played all three of the, but did not finish either.
Ishar 1 - Crap. No automap and cost money to save the game. Constantly have to feed party member. Items sold cannot be traded back.
Ishar 2 - Better. Simple map, savegames don't cost money but items still cannot be traded in for money. Still have to feed my party members from time to time.
Ishar 3 - Better than the rest of them but STILL need feed my party constantly.
Conclusion: It might be a fun game to play back in the early 90's but with so many good RPG around, I would rather spend my time elsewhere.
Just my 2 cents.