I don't have a comparison screenshot handy, but I really love the new high resolution display for PDF reading. At normal reading distance of about half arm's length I have absolutely no problems making out most PDFs, whether technical or illustrative. The only problem I've had so far is one chart in one PDF which contained fonts so small that I had to enlarge on my iPad as well.
Just one example I happened to have underhand. I can take others of varying PDF books if anyone is interested. Light ~14, contrast @max:
