Yes, it is pretty bad. Typical SONY crap - I experienced it with their laptops and with various PSs. I always promise not to ever buy a SONY product again - but somehow... gotta give them credit, in a lot of ways, their hardware is great. But they are, after all, a hardware company - and it shows when they try to do software.
The slow down issue with annotations is particularly bad. If I pop in my SD card with 500+ PDFs with annotations, turning pages can take up to two minutes, especially if I have the 'freehand' option turned on.
Frankly, it's not the end of the world - I don't need all my files with me - I was doing it mostly for backup purposes (libraries seem to not transfer well from PC to PC and I fear my laptop dying on me and me losing all annotations - hence the SD card). But it's a hassle, and their advertising just rubs it in.