I got tired of the myriad of inaccuracies, sloppy scholarship, and proprietary nature associated with the New Testament Greek texts and decided to start collecting my own accurate electronic versions. I have gone through hundreds of websites and several Bible programs collecting copies of the various Greek texts . . .The whole post is worth reading.
. . . . Common sources such as the Online Bible, Broman, Unbound Bible, and CCAT all had various errors. Not one single text for any version I examined was entirely correct, although a few were really close . . . .
. . . . I have since begun looking at the morphological parsings and links to root words, and am even more appalled at the magnitude of errors. It is far, far worse than I ever imagined . . .
Update (23.52): James Tauber's comment is worth adding here as an update: "As I've just noted in an email reply, people continue to distribute very old versions of the morphologically tagged texts that have continued to be corrected and made available at MorphGNT.org.
It is a wasted effort to try to correct these older versions when much newer versions are available. They are still not perfect, but are a much better starting point."
Update (Wednesday, 7.36): See too the helpful comments from Rick Brannan, beginning "Wherever possible, Logos/Libronix uses texts and databases from known, reputable sources. Thus our editions of UBS4 and NA27 -- different editions, with paragraphing, casing, accent and punctuation representative of their printed edition -- have solid pedigrees; they're not simply downloads from some anonymous web site . . . ." But read the whole.