I dunno about that - I really wanted to like Sparrow for iOS (aside from a couple bugs dealing with insane volumes of email, I love it on the desktop) but it never felt quite right to me.

I've actually just now reinstalled it to check what bothered me so much, and it's the same issue I have with the new Gmail app: swipe-to-archive simply isn't there. Frequency of me archiving messages: extremely high. Frequency of changing between different folders: nearly zero. Yet the left-to-right swipe which gives you the "delete" button in Mail brings that weird Facebook-esque hierarchical navbar that's become so prevalent in the last couple years.

Swiping the other direction exposes five options, two of which (I assume "archive" and "delete") have rather ambiguous icons. Mental energy - do not like (see also: new Gmail web UI).

When viewing an individual message, it's two taps to do all of the stuff that takes one in Mail. The designers traded always-visible icons for extra message real estate; clearly a matter of personal preference, but the wrong one for me.

Just goes to show how oddly personal the email experience can be, especially when you consider everyone's various workflows.