In the Marburg Colloquy the Lutherans and the Reformed forever parted company over the meaning of the presence of Christ

Present everywhere, huh?

You can read a transcript of the Marburg Colloquy of 1529 online here.

About it Gene Veith here points to "the different approaches not just to the Sacrament but to the Bible and, above all, to Christology."

This is most certainly true, but it is the different approach to the Bible I think which is paramount, for it is from the Bible that Luther derives his Christology and all his doctrine. Its articles of faith dominate independently and are not to be put at war with one another:

"Every article of faith is a principle in itself and does not require proof from another one."

Luther defends his understanding of the Holy Supper on the basis of the plain meaning of the words of institution from the Synoptic testimony, whereas the rationalistic reformers venture far and wide over the ancient fathers and the text of Scripture in their debate with Luther, but end up appealing especially to John's Gospel to argue against Luther's understanding of that Synoptic testimony.

For example, Oecolampadius of Basel opened the meeting with a salvo which takes Christ's presence at the right hand of God in heaven so narrowly and literally that for him Christ couldn't possibly be present bodily also in the Holy Supper at the same time. But for Luther, "this is my body" means both things can be true at the same time because Scripture says so, even though we cannot understand it.

In this Luther refused to make Scripture the enemy of Scripture (of course, his problems with James for example show that if he thought there were differences which couldn't be reconciled, well, then the offending Scripture must not be Scripture). 

If anyone ever doubted Luther's devotion to the authority of the text of Scripture to the exclusion of all else, one need only meditate on this excerpt from near the conclusion of the meeting:

"The important thing, as Augustine says, is that the words of the fathers must be understood in relation to Scripture. If they seem to run counter to the Scriptures, one must clarify them by interpretation, or reject them." 

Martin Luther, sovereign theologian, sovereign individual.