Marshall - 3:59 am on Dec 23, 2011 (gmt 0)

Just noticed this:

would you have a different product description on your site than the one you would have in your feed for google products? (The reasoning being to avoid duplicate content)

Google wants the same product description as it appears on your site. In fact, they often do a quality control by asking you to compare select pages to the feed for accuracy. In the Merchant Center you will see under Data Quality a line saying "Items to Assess Quality of your Data" where they will list random pages to check against the actual feed.

Marshall