OS X Lion is out, and all Haystack Software apps are compatible.
Arq 1.7.7: online backup to Amazon S3
SyncPhotos 2.0.7: sync your iPhoto Libraries across computers
Duplifinder 2.0.3: eliminate duplicate photos
If you do happen to run into an issue with any of the above, please email support@haystacksoftware.com and I’ll address the issue very promptly!