Building Magic AI - Forge, xMage, or Magearena?

[kswenito]

My main question is, which platform do you think is better for rules and card implementations?

Which platforms more accurately capture MTG rules nuances?
Which platforms do you think have more bugs?
Given that Magearena operates under a simplified rule-set and has fewer cards implemented, I'm inclined not to choose that. Obviously the rules simplifications make it easier for AI to preform, but other than that, any reasons why I should choose it?

Any other tips from those of you who have contributed to these AIs!?

Background: My goal is to try my hand at building a search based AI, possibly with some machine learning involved. I want to build it in a near-realistic play environment, but focus mainly on building the AI - so I'd like to start with an established engine. I know these engines already have their own AI implementations - and I've poked around with them - but i'm just looking to gain experience building my own.