Gmail and Google calendar will work fine on WP8. Other Google services are lacking, however. There is no good G+, Drive, Yahoo, Hangouts or GMaps apps. I also have a Lumia that I use on occasion, but I find it difficult due to the lack of Google apps. My contacts synced just fine, and the calendar stays synced, but I use the other stuff too much to move over full time from my Rezound.
The phone itself is quite solid, and for me, has worked well. I do a LOT of email on the phone, much of it on gmail, as I have several accounts that funnel into that account. It's not quite as intuitive as it is on Android, but it does work.
I don't use Google calendar, but the native calendar app on the Lumia works. I especially like how the lock screen can show calendar events for the current day, and it syncs with my facebook showing birthdays too. No excuses now for forgetting someone's birthday.
This phone is a great choice. It does have a google map+ and is great. Google mail and google calender works great with the new phone update. It allows you to sync and distinguish several different calenders. I have Outlook live, google, yahoo an facebook. This phone has many useful features and is solid. The camera is awesome.
I've had mine sine the end of July 2013 and for me, and being a fluid Android user,it was the best phone to get.
I even told my gf, who's a die hard Apple consumer, that it was better than the I-phone.
But today, I'm taking it all back. The phone froze and trying to get any help on this website is ridiculous.
Finally found out how to "hard reset" the phone, since there's no way to remove the battery.
Now it's stuck on a black screen with two white gears turning and have been turning for the past 2 hours and there's no way to shut it off.
Called tech support, and now they're sending me a REPLACEMENT phone, NOT a new phone.
So my answer to you is this...
If I would of known that this phone had problems like this, I would of stuck with Android and gotten me a Galaxy Note II.