Warren,
The results when using either Power Director 10 or Vegas Pro 11 to edit the MVC 3D footage from the Sony HDR-TD10 are excellent. I have prepared several 3D Blu-ray movies using these editors and they look superb on my Sony VPL--VW95ES projector when displayed on a 100 in. wide screen.
The processing time for rendering the edited footage is not bad at all on my 3.1 Mac Pro 8-core computer. My typical productions are 20-30 minutes in length and render out ot a Blu-ray compatible files in about an hour or so. There is nothing slow at all about using either of these 3D NLE's under Boot Camp on the Mac using Windows 7 Professional 64-bit. Of course, since these programs are 64-bit they can make use of all of the memory that you have on your Mac Pro. I have 12 GB and both programs work well. I can tell you that neither NLE will work at all under an emulation like Parallels. I can also tell you that editing the MVC files from the HDR-TD10 is very demanding and you need a fast CPU and a good graphics card since both of the aforementioned NLE's make use of the GPU of the graphics card. I am using an nVidia GTX 285 card on my Mac Pro. I am able to play back MVC clips from the HDR-TD10 on either of these programs at full frame rate, but when I add transitions or filters to any of the MVC clips then playback of the timeline slows down significantly unless that section of the timeline is rendered.
I have both Power Director 10 and Vegas Pro 11 because each has its own advantages, but you certainly don't need both to edit 3D footage from the HDR-TD10. Vegas Pro 11 is the more powerful editor in terms of professional features, but it does not allow you to burn a 3D Blu-ray disk with 3D menus. (You can burn a 3D Blu-ray disc from VEgas Pro 11, but not one with menus.) Power Director 10 is aimed more at the consumer market, but it is nonetheles a very powerful 3D editor and does allow the creation of 3D menus which look quite nice.
I love working on my Mac and don't like the fact that I have to use Windows software under Boot Camp for 3D editing on the Mac. However, there appears to be no hope of Final Cut Pro X ever supporting 3D footage from the HDR-TD10 and since Adobe did not include the ability to ingest footage from the HDR-TD10 in Premiere Pro CS6, there is simply no way of editing this footage on a Mac except using Windows under Boot Camp at present and likely for the foreseeable future.
Tom