If you run a site with thousands of subscribers that depends on FeedBurner for serving feeds, it's a little worrying. There are things you can do to reduce the pain but it's still a sticky point.
The former. I can see why my message is ambiguous now, but I'm worried about sites being at Google's mercy, rather than criticizing them for using a service that, at one point, was run by a well staffed and very competent team.
As far as Google acquisitions go, FeedBurner was by far the worst IMHO in terms of really sucking the heart and soul out of a product.