Syncing Google Accounts with iOS5

• Note to self for future reference.
• Am heavy Google services user here. Amongst others, Email, Calendar and Address Book (Contacts) all on Google. Until now, have not been able to get sync with iOS4/5 properly, especially address book. iCloud introduction (yet another email+others) has added to confusion.
• Finally figured out how to sync properly. No more duplication all over the place (Mac, Google, iCloud, e-devices). Everything now works exactly as I expect it to, when I want it to. The important thing is to turn on each service in 1 location only. Here's what I mean :=
• In iOS5, go to Settings / Mail, Contacts, Calendars.
• Add Account / Gmail. Turn On - Mail, Calendars and Notes.
• Add Account / iCloud : Turn On - Bookmarks, Photo Stream, Documents & Data and Find My iPhone only. Keep everything else turned Off.
• Add Account / Microsoft Exchange (for above Gmail account) : Turn On Contracts only. Keep Mail and Calendars Off. Instructions on how to set up Exchange is found here.
• 3 main problems I had before eliminated. Contacts updated anywhere (Gmail, iDevice) is now synced everywhere in seconds (on home wifi). Same for Calendar. No longer have to worry whether Notes made in ios5 is stored in iCloud or Google. Also a copy pops up in Gmail automatically.
• Can easily add more email accounts but be sure to turn on Mail only for each additional account. 
• Reason I don't use iCloud for Contacts, Notes etc is I think you can only work on them on your iDevice, not on your computer. Not the best route if you have a lot of data to key in.
• [Contacts all centralized in 1 place on Gmail cloud. Easy migration to other mobile devices. No need for SIM cards, etc. For peace of mind, can always backup locally via Gmail / Contacts / More / Export. If you're seriously kiasu, keep this file in your Dropbox folder! (=2 cloud + multiple local HDs)].