Don't use that guide. In fact, don't use the gmail option either, if you can help it.
Use google's own advice which suggests setting it up as a Microsoft Exchange server. that will get you syncing with mail, contacts and calendars. But the main benefit is that it gives you true push syncing!
It's probably a little redundant, but here is a shortened version of the list of instructions.
- Select Microsoft Exchange account
- In the Email field, enter your full Google Account email address. If you use an @googlemail.com address, you may see an "Unable to verify certificate" warning when you proceed to the next step.
- Leave the Domain field blank.
- Enter your full Google Account email address as the Username.
- Enter your Google Account password as the Password. (If you are a 2-step verification user, please use an application-specific password instead.)
- Tap Next at the top of your screen.
- Choose Cancel if the Unable to Verify Certificate dialog appears.
- When the new Server field appears, enter m.google.com.
You can then choose which items to sync, choose whether to keep existing contacts on the iPad etc.
Using iCloud doesn't really add new features for a Gmail user.
Contacts
Contacts on iOS are perfectly synced when using Google via Exchange.
Contacts on Mac OS X are synced using Address Book "Sync with Google" feature.
Calendar
Calendar is a bit more tricky.
On iOS, you have to activate each calendar individually in http://m.google.com/sync. But then, it syncs perfectly.
On Mac OS X, it can also be added to iCal, except it's via "Delegates".
It works but doesn't feel as just work as iCould does.
Mail
Mail has it's quirks, too.
On iOS, via Exchange, it doesn't bring all the Gmail goodness (archiving, etc.). And it miss push via the Gmail template.
On Mac OS X, via Mail, it's the same, archiving puts the mail in an "Archive" folder instead of the "All Mails" one.
Using an app like Sparrow resolve this issue.
To conclude, iCloud, like using the iWork suite instead of say Office, doesn't add value, but it feels more integrated with the OS (whether it's Mac OS or iOS).
Best Answer
No, I wouldn't say you're missing anything. As you say, Google will continue to support any configured devices beyond January 31, 2013 (from http://googleblog.blogspot.ch/2012/12/winter-cleaning.html):
so no changes for your devices whatsoever (from http://support.google.com/a/bin/answer.py?hl=en&answer=2716936):
For new devices, or if you wish to stop using Google Sync on your devices, check these links:
CalDAV for iOS devices: http://support.google.com/calendar/bin/answer.py?hl=en&answer=151674
CardDAV for iOS devices: http://support.google.com/mail/bin/answer.py?hl=en&answer=2753077
As a side note: Windows Phone users, on the contrary, got an extension and Google will accept new device connections until July 31, 2013 (from http://support.google.com/a/bin/answer.py?hl=en&answer=2716936):
See also this blog post.