Here's a quote that summarizes ECT:
The simple fact is that any honest Protestant or Roman Catholic can see that this document, for all its assiduous claims otherwise, compromises both the Roman Catholic and Protestant positions. Both sides have to admit that one can not firmly believe that the message he preaches from his pulpit is true and believe that the message preached by the other is equally true. The contradictions are too large to be hidden by the language of a document such as this.
I agree with the quote. There are too many differences. And chief among them is the teaching about Mary.