Well, the image quality is better.
Not hugely, but some of the text is easier to read, there's a little less artifacting.
I just wanted to bring it up to the same dpi as Issue 2, basically.
Thanks for the explanation. I can in fact see a slight difference in the boldness of the text in at least one place, though the difference is very slight. Whether it's worth the very much larger file sizes and slightly slower page-rendering performance is debatable! I can understand your wanting to make the standard consistent across issues, though in my view there are real advantages in keeping the file size smaller, and I think I'll retain the old PDFs myself, especially given that there are no corrections in the new larger versions.