So far the best custom map ive played was Warfare v. 1.3. Incredible detail and variety yet manags to be balanced. Each of the 8 factions has its unique scripts and starting area quests, making the map very varied depending on who you start as.
Did one game on the normal difficulty where ai gets no advantage and disadvantage and had some troubles early on. Tho the power of OP necropolis was too much when i got the combo artifact and ended up running around with a level 30 hero and about 7k power liches, 1000 in every stack.
"South-Korea is the only nation whose national sport has a sequel." -Disc
I always liked the story oriented maps. Some of them play a lot differently than a random map, almost as if you're playing a different game for that one map. I don't remember the names of the maps right now, but I do remember I loved the maps made by Timothy Duncan.
Rusty Bicycle: Rust is the perfect brake. Did the hooker just punch you in the face? -Winston
Big map, tons of artifacts, tons of stuff to explore, and you feel like you're doing very well and then all of a sudden the very powerful enemies find their way to you and kick the crap out of you.
I failed my first attempt at it (not knowing a certain combination of an artifact and a spell that might have let me face down these enemies) and am now in attempt #2.
One thing I did do to make it a little easier (I don't want to use the artifact/spell trick if I can avoid it) was to make all of the random castles become the same type. So, at least I (or the enemies) can stack multiple castles worth of armies if they manage to take multiple ones. There's still some variety, and a few hardcoded ones of each type so there's still plenty of variety, but it does make it a little easier, so you're not just running around with the level 6/7 army types from a bunch of random castles.