The latest offering from Tyndale Tech (a nice resource prepared by David Instone-Brewer) is a review of the Stuttgart Electronic Study Bible (SEBS), which features electronic editions of the Nestle-Aland and Biblia Hebraica Stuttgartensia critical texts, as well as their respective apparatuses. Instone-Brewer concludes: "give away your paper BHS + NA27 and buy this. An extraordinary conclusion for someone who doesn't like Libronix, but this is an extraordinary product which is more usable than the paper versions." Jim West is a little more skeptical, and counters: "No. Don’t. It’s never proper to replace an easily portable, non electronic, easy to use reference tool for one that requires a battery or a cord. But, do take his advice seriously if you are looking for an electronic supplement to your print collection." I'm always loath to disagree with Jim West, but I'm not sure that I would describe the BHS/N-A apparatuses as "easy to use." When my first Greek instructor introduced our class to the N-A apparatus, he told us that we were learning not one but two languages: koine Greek and the countless sigla of the apparatus. Furthermore, in order to weigh manuscript evidence properly, one must learn the provenance and relevance of all the papyri, uncials, early translations, and other versions which appear in the apparatus. That's a lot of information.
In an electronic edition, all of this information is available at the click of a mouse. Instone-Brewer mentions that a slightly less powerful, less expensive version of the SEBS is also available from Accordance Bible Software; I have used this version for the past year or so. (I also recently purchased an Accordance edition of Bruce Metzger's Textual Commentary on the Greek New Testament, which is included in the SEBS reviewed by Instone-Brewer.) My verdict: I love the feel and portability of my Greek-English New Testament, but text-critical work is much simpler in the digital world. Explanations of sigla and the provenances of manuscripts appear simply by placing the cursor over them. The apparatuses can be searched with ease according to scriptural references, critical signs, witnesses, etc. In preparation for an exegesis class I'm taking this fall, I wanted to see how papyri have affected the development of the Nestle-Aland text from the 25th edition to the present 27th edition, with particular emphasis on the Letter to the Hebrews. I simply searched the critical signs for the cross (which symbolizes a reading which was part of the 25th edition but has now been changed), restricted the search results to Hebrews, and noted that almost all of the changes were supported by the papyri. Pretty easy.
In short, I'll probably keep my paper editions... staring at computer screens all day makes my eyes tired. ;-) But I highly recommend electronic apparatuses to all serious biblical scholars.