So I'm sitting here getting ready to start an effects heavy commercial and asking my self if I should dive in and try to do it with FCPX or just use 7. I've come to the decision that taking round tripping to Motion away is going to make this thing far more frustrating than having to wait for a clip to render.
Starting up good 'ol FCP7
THANKS APPLE! for taking away round tripping!

I too find it hard to believe that they don't allow round tripping. Apple says we should buy motion and compressor to do many things that are not included in FCP, but then doesn't allow us to "Send to Motion." Huh? It doesn't make sense.

Apple didn't "take anything away." This is entirely new code. They haven't implemented it yet but it's certain to come. Motion's Rigging and Publishing are major steps forward. Round tripping will probably happen in an update.

I really miss motion round tripping, but I'm really starting to see the power of motion 5 integration that's included from the get-go, especially rigging.

Example: I made a background plate for some greenscreen footage, just a nice 5 minute static vista view from a mountain overlooking a city. I wanted it to have a more shallow depth of field so I softened the background with a blur, but the ground in the foreground was as blurry as the farthest point. I wanted the foreground to be blurry, but not as blurry as the mountains miles away. So I doubled up the background layer and on the top layer I masked around the foreground in the shot. I then applied a gaussian blur to both clips, but set both blurs to be controlled in a rig by 1 slider. The minimum blur for the background was 8 and the max was 64, the foreground minimum was 4 and the max 42. So after publishing the rig and saving all I do is add the new generator below my keyed footage and I have 1 slider that controls the "DOF". When the slider in FCPX is at 0 the foreground is blurred by 4 and background by 8, if it is set to 100 then the foreground would be blurred by 42 and the background by 64, and values in between scale accordingly.

This was my first step into rigging and I can see in the future rigging up way more complex and powerful generators/effects that I can control quickly like this through final cut x