Google Sitemaps

[Allfetish]

http://www.google.com/webmasters/sitemaps/login

I'm curious what experiences others have had with this. I submitted a simple sitemap with a listing of urls for one of my sites. What I noticed was that the googlebot seemed to crawl a bit more often than it used to. It seems like a wonderful tool to help with efficient crawling. Particular if you actually set up a XML sitemap using all the features.

However, I ahve also heard complaints from people who have said after submitting a map they actually lost their listings. So far nothing like this happened to me. I am curious what expoeriences others have had?