Since the Amber Update Gmail works fine, as does Google Calendar, both in the Native WP apps.
Get Metrotalk for Google Voice. It takes a few moments to configure but once you do it works as well as Google Voie for IOS including the ability to call from the App.
I too just switched from Android and I'm still on the fence. Most of the Apps I use are here but the are some near dealbreakers like Sirius/XM and my IP Camera app that are not present and probably never will be.
On the other hand, there are a lot of nice included features like SkyDrive and Nokia Pro Cam. Unfortunately, the choice is not clear cut. You have to figure out whats important to you.
I myself was hell bent on being a one device guy. Had the Galaxy Note and Note 2 so I'd have EVERYTHING all at once. Now with the Lumias (especially the 1020) getting such great cameras I may stick with Windows Phone. I do still have an Android Tablet though to get me by.
Then again, Sony's stuff at IFA like the Z1 or the QX cameras are so intruiging. Though, the Lenses won't work with Wndows Phone, or any phone bigger than 5 inches.
So, once again, I'm left scratching my head. Do I go back to the best all around device like the Galaxy Note 3? Or do I stick with the best camera? Or do I compromise, get a middling Android Phone like the S3 or Optimus G so I can slap one of the Sony QX lenses on it? So many decisions!
Devices owned (Yes, I Have a problem)
Iphone 3GS, and 4, Archos G9, Acer Iconia Tab, Asus Transformer, Dell Streak 5 and 7, Galaxy Captivate, Tab 7, and 8.9 Galaxy S2, Captivate Glide, Note 1, and 2, Mega, HTC Amaze, LG Optimus 4x, Sony Tablet S, Tablet P, Xperia Play, ION, X10, X10 Mini and Xperia Z, Pantech Flex, Pantech Sky Vega S5, Toshiba Thrive, Pantech Element, Nokia 808 Pureview, Motorola Backflip, Xoom, Razr, Razr HD, Huawei Ascend Mate, Nokia Lumia 920,LG Optimus VU, Pro, HTC One.