I’m having the same situation but i return back to final cut to do some lat min edits. Playback ends up lagging big time so exporting on NTCS DVCPRO 1080i seems to help play back just fine the only problem I have is then I have to constantly render whenever I do slight changes on FCP. Is there another export option you would recommend? this way I not only dont lose the quality of the export from AE, and still be able to edit last min touches in FCP? I know it sounds like a lot lol