People will complain about anything. I've been a paying member of ancestry.com since the late 90s and in all that time there will invariably be someone who starts a thread just like this one at least a few times a year. Do you pay site virgins honestly think this is the only site out there that does what you accuse ancestry.com of? I personally don't care for it and think it should be easier to figure out how to cancel an account, but it's the nature of the beast. I've learned to start writing down contact phone numbers BEFORE I pay for access to a site.
As to people not posting their trees, well I for one say if it cuts down on the junk that incompetants post then they need to start ripping off more people. 90% of the "trees" I see posted are copied willy nilly from someone else and it cascades exponentially to the point that the whole "world tree" is infested with pure hokum.
"Cluttered mess of advertising"? Give me a break. There ARE programs out there to prevent it from appearing.