Browser based editors for SDL Tridion Docs r14 sp3

We're currently considering Collective Spaces for collaborative reviews and DITA authoring for internal folks outside our immediate organization. We understand that Collective Spaces is available for those purposes, but we also want to compare it with other available options (just "doing diligence") before potentially moving forward.

Does anyone know if other browser-based editors are available with verified SDL Tridion Docs r14 sp3 integrations? Many thanks for your help in advance.

Paul M.
McAfee