I'm glad that I got to grow up in the 70s and 80s and play the early editions of D&D as they were released. Even though I sold off my copies over the years, I've managed to replace all of the core materials I need to run OD&D, Holmes Basic, Moldvay/Cook/Marsh Basic/Expert, first and second edition AD&D. For me, the OSR was just getting back to my roots and playing the games that I loved.
When Wizards of the Coast started releasing PDFs of old game material years ago, I jumped in with both feet and ordered a lot of titles. I still have those files, and they have seen a lot of use over the years. When WotC pulled the PDFs from the market a few years ago, I was as outraged as everyone else. I still wanted to be able to buy more than I owned at that point. I carefully backed up the ones that I had as I moved from computer to computer, waiting anxiously for the time when I could either add to the collection or get better copies of what I already had.
The latter was a definite wish. The original PDFs were buggy, inconsistent, and in some cases just plain bad. Some of the scans were misaligned or misrecognized (or not properly recognized at all). Most of the text was difficult to use in any other form than the original scan. Searches didn't work well, and contents and indexes didn't point to the correct places in the files.
Now that the older D&D material is available in PDF again, I'm looking forward to replacing everything I purchased before and adding as much as I can to the collection. I've had a chance to download a few different titles, and it looks like WotC has managed to correct all of the flaws that plagued the old files.
I downloaded some of the free files available (B1 In Search of the Unknown, H1 Keep on the Shadowfell & Quick-Start Rules, Khyber's Harvest) and ordered a new copy of the Moldvay Basic Rules. I'm happy to report that the scans of B1 and the Basic Rules are clear and easy to read. The files for the others are obviously based off of the electronic masters for those products. All of them have solid contents outlines which allow you to click through the sections in the files quickly and easily. Short of recreating the original layouts in the older products, these are everything I could have hoped for in these products.
I went to a Great Books college, and one of the things that we constantly harped on there was going back to the original source. If you want to argue for or against something, you should know what the original source of the argument says. A lot has been made over the years of the evolution and changes that have happened in D&D and the way we play the game. Fortunately, we have clean copies of the originals available to refer to again.