I spent 3.5 hours Saturday night creating and lightly optimizing a completely new data feed (or bulk upload) to get PersonalProtectionStore's home security products up and running on Google Base. PersonalProtectionStore uses Yahoo! Merchant Solutions which allows me to download a catalog and associated information, but it's not in a format compatible with Google Base (superfluous fields in the catalog, non-uniform field names) and the dowload brings with it special characters and HTML code which cause listing errors. Additionally, there are many fields Google Base makes optional which my catalog did not include. These additional fields help with data feed optimization (DFO).
Froogle feed submission used to take a couple days (and a couple iterations) to process correctly, so I was pleasantly surprised to see my feed accepted in less than an hour. More importantly, by the time I checked back early the next morning, my products (and images - this used to be a major issue with Froogle) were up and running. My feed of 153 products consisted of 30 errors which weren't explained very well, but overall it was a smooth process. [It's important to note that I've submitted hundreds of feeds to multiple engines. There are plenty of people on the Google Base Help Discussion Group having problems.]
Submitting to Google Base gets you listed on Froogle. Being in Google Base or Froogle potentially gets you in the Google Onebox product search results in a regular Google search (just under the Sponsored Links and just above the organic results).
While I've been critical of Froogle's Spam problem, and I'm not sure what to make of Froogle's recent update (more info soon), I did say in early April that it's time for merchants to submit their feed to Froogle (Google Base dashboard has now completely replaced the Froogle Merchant Center). My 3.5 hour experience only strengthens that argument.
For good or bad, many merchants are completely reliant on Google for sales, obsessing about optimizing their sites for better orgranic listings and feverishly spending on Google Adwords. Just don't forget about submitting your data feed to Google Base.
If you're having trouble with the your Google Base data feed, there are many companies which can help you out with feed management: ChannelAdvisor, ChannelIntelligence, Performics, Mercent, Vendio/Andale, Marketworks, RedZoneGlobal, MerchantAdvantage, etc.