I just wanted to post a quick rebuttal to MS. Many of the issues he points to are entirely legitimate. However, as a professional performing orchestral trumpeter, I just wanted to put in my two cents because I disagree with the general tenor of his post. I do not see the use of scanned public domain parts as a low-quality solution, nor is 8.5x11 paper unacceptable or problematic.
On the "do-not-do" list, I definitely agree that bleed-through and cut-off staves are unacceptable and clarity is very important. However, I disagree that most parts are significantly shrunk that much to fit into 8.5x11. Most of the large-format "originals" have quite a generous border of blank space. The scans from the Orchestral Musician's CD-Rom Library (which I own have all 10 volumes of) remove this blank space which results in only a small shrinkage. The small size is generally not a problem for myself (not yet being 30 years old) except with some extremely illegible editions by French typsetters in the early 20th century (original Mahler 6, Don Quixote come to mind). Furthermore, PDF technology regularly includes "fit to page" scaling options, which when used, simply remove the problem of clipped staves.
All of the details of printing that are a problem are, in my experience, exactly the things that a good orchestral librarian or print shop should and do know how to handle. Orchestral librarians is particular make practice copies of string parts all the time on 8.5x11 parts and the ones I've worked with are good with a photocopier and know how to create a good tape binding.
For my personal practice and performance use, I regularly use PDFTK (a linux pdf manipulation utility) to assemble books of repertoire for the season from IMSLP and OMCRL parts and email it directly to my printer (not staples/kinko's, mind you. A real/professional printer) and have them print on regular 20lb paper, double-sided, with a coil binding. They do this without batting an eye and the parts are crisp, no bleed-through (laser printed), and the pages easily turnable. I've been doing it for years and never felt wanting for those oversized originals that you can't fit in your case without mangling them.
One very good point that MS had is that there are a large number of original typesettings out there that were just poorly done. Even so-called "edited edition" by Neuwig in recent years, while readable, are rife with errors. I have a fair bit of contempt for bad publishers/editors and sometimes a public domain edition will be quite bad with an "updated" newer edition. In these cases, I agree that musicians certainly appreciate having the best available parts to play from and are happy to complain to editors and publishers about how to do their job better.
When I one day am lucky enough to have earned my place in the ranks of very well-paid musicians in a major symphony orchestra or opera house in America, I will be happy to pooh-pooh the cheapskates who can't bother to buy us a real set of parts that my aging eyes can read (for surely I'll be old before I get there). Until then, however, I personally think the availability and use of these parts bring simplicity and convenience to my life and their quality is certainly sufficient for the work that I do. I daresay I represent a pretty typical set of experiences for the "under 40" crowd of performing musicians in the Boston area.