I second the opinion that a threaded view would be great. I'd also like to see a more finger friendly way of switching between the inboxes of different accounts, and would like to suggest that when the far right icon on the toolbar is held and a specific account is selected, that modest switches to that account in the display. Selecting all would not change the displayed account. Does anyone like that idea?

Other than that, it seems to be working fine for me with two secure IMAP accounts, on mac.com and virgin.net, although I've only pulled the top 20 from each, and will not try and access the full history of each account on the device as others seem to need to.