iPhone's mail app for Gmail or Gmail's web app for iPhone?
Generally iPhone's mail app unless I want to report spam or easily view a conversation if the text wasn't included in the reply. - Tony Ruscoe from fftogo
web app. Much faster for me, and it can do much more. - Matt Cutts
@Otto: I'm pretty sure the web app *does* use Gears. Problem is, parsing Javascript is slow as hell on every phone I've ever seen, including the iPhone (think seconds, not millis). Plus, you're forced to use the browsers crappy layout engine, with things like position:fixed and interior scrolling areas disabled. Mobile vendors (including Android) need to do a lot more to deal with this situation before web apps will catch up with natives. - Joel Webber
Good point. I guess I could move it to the Spam IMAP folder... - Tony Ruscoe
Otto, webapps does use Gears to do offline caching. <--- [Added: I think this sentence is wrong. I believe it's HTML5, as Jérôme said.] Esp. with the 3GS, I noticed a distinct speed jump when I upgraded because the 3GS handles Gmail's JavaScript much faster. For me, the webapp hasn't been slow, and it's just much closer to the Gmail experience. I need threading and all that stuff. - Matt Cutts
The "older version" of the web app is *much* faster to load for me than the new version (on both an original and 3gs iphone). Just click the "older version" link in the footer and bookmark it. - Ben Darnell
Sorry, it might not be Gears--I think you're right that it's the HTML5 that provides offline. - Matt Cutts
And I think it's the same on Android (for the GMail webapp) I don't think they use Gears for GMail webapp on Android. For me it's the native to quick look at the received mails and GMail web app when I need to do anythin other than read. - Jeremy
re:gears vs. html5 -- I always conflate the two, but really all I meant is the app cache and database APIs. The javascript appears to be a large part of the speed issues, but the HTML DOM's no speed demon either. And when you compare the speed of the Android native client to the web client, and consider the the Dalvik VM's pretty slow as well, it implies that Javascript *parsing* (startup time) and the DOM are likely the big time sinks. - Joel Webber