Let me qualify by saying I'm wholly in favor of video editing on the Linux platform. I have used MainActor for a couple of DVD projects over the past 4 months. It's fast, it's inexpensive, it does the job; I'll put up with it for what it's worth.
Feature for feature, I'd compare it to Premiere 6.5. Final Cut, Premiere Pro, and especially Avid HD outclass Mainactor in my opinion, due to their more stable, predictable behavior.
MainActor 5.5.7 still has numerous bugs in the export module and bizarrness within the interface design that you wouldn't find in a more tightly managed software project. I'm nonplussed at the support offered via message board. Directly speaking with developers is nice only in theory: engineers should be busy engineering. They shouldn't be ask to test, design for the user, or offer technical support.
Obviously MainConcept's staff is small and I laud them for continuing to improve upon MainActor. Mainly, they should just continue to fix bugs, consult a usability expert, and provide a professional technical support staff. Even some lady in India could provide a better impression to customers than an overworked German programmer 