Currently, only Omni Systems Mif2Go offers OmniHelp output. That could change as other vendors become interested in the possibilities, both of major cost savings for themselves, and of improved functionality for their customers.
Participation in this open-source project provides significant benefits for authoring-tool vendors. The lack of an open standard for cross-platform Help has meant that major resources had to be assigned to the task of creating a proprietary solution. For some of the smaller vendors, that cost has been prohibitive, and so they have not created such a cross-platform solution. But even for larger vendors who have done this, the costs of code maintenance and of updates to deal with new browser and OS versions are burdensome. OmniHelp offers all vendors the opportunity to work together solving common problems, while still preserving their own proprietary value-added in the way they generate the project-specific OmniHelp files.
An additional new factor is the Eolas win over Microsoft, which will impact HTML Help and all browser-based Help that works with applets. This means that only pure JavaScript applications may continue to be royalty-free. It also means that MS may well drop from IE support for the <object> tag. OmniHelp is one of the very few alternatives not affected by the Eolas case.