iPhone: Spark was a really solid email app when it was first released, but it was plagued by a few bugs and missing a few features. A new update brings it much closer to being a go-to email app.
Among the new editions are a new edit mode where you can delete and archive email in bulk, a delete all button and the ability to disable loading remote images. Better yet are the bug fixes, which include better battery usage, improved support for IMAP accounts, fixed syncing issues, and more.
They also removed the "read receipts" functionality, which was a pretty weird inclusion as it was. If you had trouble with crashes or support for your email account before, Spark's worth another look.
Spark (Free) [iTunes App Store]