Apple iPhone 4S

I have been an Android user for the past couple of years, and I use Gmail heavily. I love how the contact list and calendar are sync'd between Gmail and my phone and updates to either one update the other immediately. I'm considering switching to the iPhone, and I'm wondering if it's possible for Gmail, calendar, and contacts to integrate the same way?

Also, how is the email on the iPhone? I heard all your email accounts have to be in one inbox - is this true? I like to keep my personal and work email in separate apps.