Thanks guys, helpful insights and comments.
John, totally agree and I understand we are talking playback viewing and not full quality. But I think FCP is definitely the low man on the totem-pole here. RT playback gets shut down pretty quick. I think I probably should have separated it into 2 questions.
How anything handle RT preview playback of mixed codecs and frame rates. Then dropping delivery codecs like H264 and the like. Not asking SHOULD you do this but CAN you do this. Seems like Vegas and PPro have the lead with this.
Then how well does the export handle frame rate conversion. Especially if you are dropping 60i or 30p footage in a 24p timeline. (this type of conversion I would do in Shake or suggest other heavy lifting apps).
Great video Dennis. CS5 look awesome and I do have the trial version going and will probably get the Production Suite when that expires. Hopefully this will also light a fire under Apple to get all the pro apps to 64 bit as quickly as possible.