At Google, the bungling of the iOS GMail app launch goes deeper than the bugs the first, short-lived version of the app threw off when it was fired up. The app is unfortunately a typical product from Google's Mail group: It has most of the useful features you want, but it's missing the one or two you need. And it's designed for engineers. With fingers the size of pipettes.
Its competition is the e-mail app built into every iOS device. That app is by necessity general; it works on almost every e-mail back-end there is. It lacks access to several GMail features. But it's fun, fluid, and pretty.
Google's GMail app is a big step up from the Apple app in key areas: It's easier to label and star incoming messages and to attach pictures to messages you're composing. And it has the de facto "pull down to refresh" behavior that pretty much every app except Apple's own e-mail app now has (seriously, Apple).
But it's laggy and occasionally choppy, which the Apple app rarely is. And it only supports one Google account, which makes it useless for anyone who's truly invested in the Google vision (if you are, you probably have more than one Google Mail account). Google's Android GMail app is better. It has a more app-like feeling. It feels like Android, not the GMail Web site with a browser extension slapped on to it, as the iOS app does. On Android, the icons are in the right places, and you're not boxed into a single account. It's better.
I can see using the iOS GMail app from time to time, when I'm trying to handle a bunch of filing on a mobile device. It will be slow, but at least in the app you can actually do this stuff. But for just reading and replying to e-mail in a hurry, the Apple app is still better. And if you want to see all your e-mail (from Google as well as other accounts) in one inbox, Apple will give you that, as will the email clients from Microsoft, RIM, and the dearly departed WebOS. (Ugly Google workaround: Set up one GMail account to read in e-mail from other accounts, and access that account only from your mobile. I leave as an exercise for the reader the downsides of this approach.)
Meanwhile, Google is also improving its Web-based interface. The rumored re-do of the site has launched. It is better, but the site still lacks basic productivity features, like wildcard search (oh, the irony) and the capability to create a filter to show just e-mail you received today.
People who want a more app-like experience on their computer should look at clients like Sparrow (on the Mac), which is minimalist, pure, and fast, so it's great for run-of-the-mill e-mail handling. There's also the new version of Postbox (PC or Mac), which is based on the Thunderbird source code. It has tons of features to help you focus and sort e-mails when you're trying to get a grip on a big backlog of messages.
I've yet to see a truly good e-mail client for iOS that offers Apple's fit, finish, and speed, combined with the productivity features you get in heavyweight client like Postbox. There is an opportunity here, as more people do on tablets and smartphones the work they've traditionally done on laptops. But to win over Apple users, Google's got to get UI designers who think like iOS junkies.