「Merriam-Webster's Advanced」VS&#12

1, Merriam-Webster's Advanced Learner's English Dictionary
2, Collins Cobuild Advanced Learner's English Dictionary

I'm native Chinese, I just wanna buy either of them (not both), but which is slightly better for advanced learners, please tell me your reasons. Thanks!

Have you also considered Macmillan English Dictionary?

Merriam-Webster's Advanced Learner's English Dictionary

this one is the best

McKay:
Have you also considered Macmillan English Dictionary?

In fact, I've already got a longman and an oxford advanced. What I need else is either "merriam webster's advanced" or "collins cobuild advanced".

Tom, Why don't carry out a review for Merriam Webster's Advanced ?