I've read those books, and I remember vividly the description of a world with several moons, where the sea was gradually swallowing up the land.
They are very well written and Morgaine is a really great heroine. But I missed some things in those books.
For example, there is almost nothing about Morgaine's past. As far as I can remember, none of the books talk about the life she left behind before she took over the gate. Who were her parents? Did she have any siblings? Or perhaps a husband and child? What had she sacrificed when she began to wander these strange and dark worlds?
If I could imagine, she might have shared first place with Merlin.
I also didn't understand much about the Khal and their relationship with humans. It would have been nice to read a prequel to the Morgaine stories that explained all this.