My experience with CodeCombat:

Pros: I liked it, and I find it fun to learn to make a game that way.

Cons: I found the "campaign" shockingly short - like 10 missions or so, and a few of them weren't even working (stuck on loading). After finishing that campaign, I found the jump to the "user-created" missions too high. I would've expected at least a 50 mission campaign, that walks me through to the more advanced concepts, until most of the user-generated ones feel easy.