No one other than the AI team has used it since it hasn't shipped yet. 'Large PDF files' is rather ambiguous, but since the SB has the same amount of RAM as the TB with a slightly faster CPU, I'm going to guess that it'll be faster, but not world-shatteringly so. AI is really at a disadvantage, since or all the new ARM devices this year are using a Cortex A9 and they're still on the A8. When mine finally ships I plan to try and replace the motherboard with a Pandaboard
if possible (which has twice as much RAM and is dual core), but it's a significant undertaking and I doubt most people would bother with it, especially as it would cost the use of the MID (the Pandaboard is much larger) and likely void the warranty.