Getting a Google domain means giving up getting new features from Google :( (pauses to clean up bitterness)
You can get a domain through google without switching your google identity to it. You can also sign up for google apps on a non-google domain. google domains and google apps are not the same thing.
That said "delayed schedule" above means 1+ years.
The one feature missing and that was painful for me were Contacts photos with a resolution higher than 96x96 pixels. On a latest generation Android with good resolution it sucks and I would have preferred if Contacts photos weren't synchronized at all. I ended up switching to a CardDAV provider and in the end I gave up on Google Apps for other reasons as well. And for the record, Google accounts had this resolution increased in 2012 ;-)