Hey, Congrats!

I loved Isles of Terra more too. Of the first generation of Might and Magic games, 3 was my favourite.

I do think Xeen was better, it's just that the crashing made it less fun to play.

For me the difficulty balance was off.

If you start Darkside of Xeen before finishing Clouds, then you get tons of XP and Clouds becomes too easy.
If you finish Clouds first, then the beginning of Darkside becomes too easy.

Maybe best way is to finish Clouds, and then play Darkside with a new party.

Personally, I felt like the beginning areas of Darkside were easy to boost a party made there to about where they'd be if they'd have finished Clouds