First my apology to the moderator if this post is in the wrong forum! The banner announcing the "New Forum" indicates that it includes the new PRS models, but leaves it vague as to whether or not posts about earlier PRS models are acceptable!
1. Turnaround time for the upgrade: My unit was returned on the 7th day after being shipped for upgrade. It may be that the "two-week" period stated by Sony is a worst-case estimate. The quick return was certainly expedited by Sony paying for over-night air shipment via UPS both to AND from the upgrade facility.
2. Memory card: I was worried about having left my memory card in the reader. In fact, Sony removed the memory card and returned it inside a little baggie and that inside another plastic bag closed with an adhesive tie AND this double bagging identified with a barcode label.
3. One note of caution: The retuned unit was not reattached to the Sony cover, so it's important to be cautious when first handling your unit in order to avoid dropping it.
4. Recommendation: Sony's directions for shipping ask that your ID number be written on the outside of the box used to ship the unit. Since barcodes are used extensively during the upgrade process (my unit had three stickered on), I suspect doing so avoids any delay in getting the unit into the upgrade process.
Overall: Kudos to Sony not only for throwing a lifeline to EPUB for PRS-500 users, but also for the quality of the upgrade process!