For Windows 7, I run that in a virtual machine; it seems slow, but that may be due to insufficient memory allocated to the VM. However, switching to use Chrome has made it rather faster.
I've been using iLetter exclusively for my mail for over six years. The features it contains reflect my preferences and it has not had wide testing. In particular note the following:
- To date, iLetter has only tested on a few mail hosts. However, I've no reports of issues.
- Some features, such as filters and searching, are adequate for my needs but others may find them a bit lightweight
- You can only import mbox format mailboxes, and similarly export is to mbox format
- No import or export of settings or filters
- The Addressbook is standalone, and is not connected to the OS X AddressBook application
- I'm no artist either :-) and the icons in e.g. the toolbar really need a makeover
- In the features list above, I've said that you can move an attachment to another place in the filesystem, i.e. out of the Attachments folder. If you do, and choose to have iLetter not take note of its new location, then that attachment will no longer be visible to iLetter, should you wish to forward the mail or export it.
But, having said the above, it should be noted that Emailchemy can be used as an intermediary in the matter of import/export. In particular it can reconnect attachments to mails in Eudora mailboxes, and iLetter will then handle the attachments normally on import. Because Emailchemy can do this job already, I see no point in doing more than I've done on this issue.