Don't get me wrong, the grammar is definitely easy to understand, but IMHO that's just another point for the 'learn early in life, or struggle' opinion. Adults have a much easier time with more complicated grammatical rules (hi, German!) or even rules with lots of exceptions (hello, Russian!). But having to remember how to spell and pronounce every other word is akin to hell for an adult. (I'm already struggling with it while learning Russian.)

Still doesn't hold a candle to Mandarin or Japanese, of course. These guys are just on a level of their own. :)