I notice that TC: A Journal of Biblical Textual Criticism has a review of the NA27 edition, with apparatus, that is contained in the Stuttgart Electronic Study Bible (SESB). If you're a user of the NA27 in SESB, then you want to read this article. Do it now.
Here's the abstract of the review article, which is a 26 page PDF.
Abstract: The Stuttgart Elecronic Study Bible is a groundbreaking electronic publication. It contains the most widely used scholarly biblical texts, BHS and NA, as well as their critical apparatuses. In this extensive review article, Krans focuses on NA27, especially its critical apparatus, though he frequently draws BHS and its apparatus into the discussion as well. He asks this question: What are the possibilities, surprises, limitations, and future prospects of the implementation of NA27 in SESB 1.0?