Personally and for my company, I've gotten away from using Google's calendars and contacts. There is a bit of misinformation in this thread, mainly that Google uses "Exchange" - they don't, but implement an an adaptation of Exchange ActiveSync (called Google Sync) - which isn't "Exchange". And, if you're going to use the EAS settings, you'd be missing out on Google Calendar's multiple notifications (up to two in iOS) and calendar color mapping present in the Gmail account type. Google's Gmail set up offers different benefits - in how iOS handles mail and calendars.
I have my work account (Google Premier Apps, which isn't too different than the free version or Gmail accounts on iOS) set up for *both" Gmail and Exchange (AS/Google Sync), and have opted to use EAS for email and Gmail for calendaring. I use iCloud for contacts, with my rationale explained deeper in another thread - Google Contacts and iOS are just a train wreck waiting to happen. I get email quickly and can push multiple folders via EAS, can set up multiple notifications in calendar (though i/we have moved calendaring over to iCloud for now). I'm not knocking Google's product - I've paid through the nose to try out their suite, and I'd suggest not relying on synching your iOS devices to Google's servers for contacts.