Like you can see at this Google forum, they all have posted many tests on what are the possible issues in Gmail latest service offering.
But on my personal oppinion, the issue that really had to be underlined is how come Google didn't test through this Gmail IMAP service on WinMob platform before they released the service for everyone to use? Seems like Google has concentrated more of their resources for making this service available for iPhone first, is this got something to do with Windows Live email service versus Gmail email service? It's been awhile now since the Gmail IMAP service rolled out, many WinMob device users are waiting for the service available as soon as possible; the same questions have been posted over and over at every Gmail & Google forums: "When will the service fixed and available for Windows Mobile?"...
Although Google has been offering free without any fees/charges for their services, still many users keep on complaining for faster and better services. Are we entitled to do so?
Of course we can use Gmail application in our phone, but you'll need to install a JAVA VM first. Even this app is free from Google, and I must say they've done a great job too. You can use almost every basic Gmail's services with that application, feels like when you access Gmail via mobile web browser itself.
Both of those I've just mentioned, Gmail app & Gmail mobile site, give you another additional ways to access your emails. But it's not the same as Gmail POP3 & IMAP services, because with those services your Treo 750 can get them automatically at interval time frames you had set before in Outlook Mobile. Which way will you choose then?