Features added earlier this year enable you to launch the appropriate Google app (if you have it installed on your iPhone) instead of launching Safari when you touch a link in an e-mail. This means that a YouTube link will automatically open the YouTube app, a Google Maps link will automatically open Google Maps, and a Web URL will open Chrome. This is a departure from what we usually see from Apple, which historically has been pretty particular about developers using the core Apple apps already on your iPhone. I definitely prefer that it automatically opens YouTube and Google Maps rather than browser-based versions, but I'm fine with Safari for most links. Fortunately, you can pick and choose which Google apps will launch automatically by turning any of these behaviors on or off in the Gmail app settings.
The latest version of the app adds a redesigned inbox and new notification options. The new inbox now sorts e-mail for you with tabs at the top separated into Primary, Social, Promotions, Updates, and Forums. The Primary e-mail tab holds e-mails from friends, family, and other direct messages; Social gives you updates from social networks; Promotions give you the latest sales pitches (including those you signed up for); Updates is where you'll find confirmations, receipts, bills, and statements; and Forums gives you the latest news from user forums you're signed up for. In my testing the behind-the-scenes sorting works great, making it much easier to scan through e-mail that's important and saving the less important messages for later.
The new notification options will hopefully cut down on constant vibrations or sounds coming from your iPhone every time an e-mail is delivered. Now, you can be very specific about when you receive a notification. You can continue to get notified for all messages, only the messages you marked as important, get no notifications at all, or on a per-account basis. This may seem small, but if you receive a lot of e-mail like I do, cutting the notifications down to just the e-mails that matter is a great option. You can customize all these settings from the in-app settings page.
One problem still remains, however. With Apple's Mail app on your iPhone, you can already send and receive messages from your Gmail account. Even with more useful features coming in each update to the official Gmail app, having two e-mail clients is not really better than having one. Still, if you're a heavy Gmail user with multiple accounts, it might be worth checking a couple of e-mail clients if you like the experience you get with Gmail.
Overall, if you're a Gmail user who likes Google's features for organizing e-mail, the official Gmail app is a good option and there are more reasons to make it a mainstay on your home screen with every new update.