When you ask about how the church that is emerging differs from the "New Testament Church," it raises a number of questions for me. Do you mean the church in the New Testament era? My sense is that there was nothing like uniformity among early churches - one gets the feeling that the Jesus movement in Jerusalem was very different from its counterpart in Antioch, that the early church in Corinth would have differed greatly from that of Ephesus, etc. There weren't any creeds beyond "Jesus is Lord" (which probably had a meaning for its original confessors that differs from what we might assume, by the way). There was diversity in structure and practice - as evidenced by the fact that Paul was trying to build some harmony at least, if not uniformity.
If by "New Testament Church," you mean an approach to church that exists today, that would also raise some questions for me. Churches claiming to be based on the New Testament today differ widely from one another: some allow women to lead, some don't. Some speak in tongues, some don't. Some believe in 6-day-creationism, some don't.
McLaren can't see the proper approach to becoming the New Testament church. Like some brethren we know who wrote a book about several approaches to "primitivism" (to say, perhaps, that all approaches are valid?), McLaren cites different approaches to restorationism and finds the sum lacking. He's fallen for the old saw about the diversity that existed, failing to see the uniformity, yes, uniformity, among first-century churches, and the insistence of Paul to get back in line when churches like the one at Corinth leave the pattern. The apostle berates the Corinthians severely for that. See 1 Cor 4:6-7; 7:17b; 11:16; 14:33b-34; 16:1. Paul even talks a lot about condemnation for those who don't eat the Lord's supper according to the instructions that he had received and passed on to them (1 Cor. 11:23-34).
However, he does seem to think it possible to "ask some primary questions such as "What was Jesus about in the first place? What was his message, his mission? How can we realign ourselves with that original message and mission in our own context today?" But the lens he uses is far different to study the issue about realignment, as he puts it, and he comes out ta a very different place than those of us who see the NT as a pattern for the gospel and the church.
There really isn't any way to reconcile the restoration plea and the emerging church philosophy. They are diverging paths and one must give up one to follow the other.