Hello, dexx, and welcome back to WindowsEight Forums.
If you're thinking of installing, I'd advise to wait for 8.1 at this point. RTM is being released in 6 days. Preorders are being taken now or one can order the ISO via MSDN or Technet if one has a subscription.
Windows 8 & 8.1 is a vast change from past OSs which is beyond explaining in one post. There's more flexibility in 8.1 than in 8 so far as the OSs are concerned. So far as services and apps, basically the same as 7. Turn on or off at will. Install or uninstall any apps whether it be Modern/Metro Store or Desktop apps. There is a whole new world within the Modern/Metro Store apps.
As far as I know, IIS is not turned on by default when Windows is installed. The IIS Manager is accessed through the Microsoft Management Console or Administrative Tools in the Control Panel.
You may want to read through the forum to get to understand what 8/8.1 are like. I can't pinpoint any one thread that would explain it all.
Hope that helps.