I loaded 4 feeds to 700 directly:
The Moscow Times, a small file, 250 pages - opened quickly, links worked, it took 10-15 seconds to change text size from S to L, another 10-15% for any other font size increase. I understood formatting was done during each increase, not all together. Second time going through the same increase was fast.
BusinessWeek and NYTimes - it took a minute to open, tried 10-15 random links, all worked. Trying to change the font size didn't work, had to reset after 5 minutes.
WSJ, large file, 9Mb, 2200 pages - didn't open, after 5 minutes had to reset.
All these files worked fine if loaded through Sony software.