Hi Maui. I've fixed an issue which will unfortunately be causing instability with After-Effects plug-ins in the current beta build - keep an eye on the Announcements section for news of updates.
I've managed to get Magic Bullet Looks working, but only by disabling some portions of our plugin support (which really do need to be there).. I'll keep trying, but may need to seek help from Red Giant to get any further.
We do our best to make AE plugins run as fast as possible, but there's an overhead in supplying images to AE plugins - we have to shuffle the component order (BGRA -> ARGB I think) then fetch them back from GPU memory into host memory; Once the plugin has processed an image we have to copy back to GPU memory and re-shuffle the components. Component shuffling is very fast, but GPU <-> host can be a bottleneck.
Lightworks is capable of replicating (in real-time) most of the looks that MB Looks offers, although we don't presently offer an arbitrary 'curves' effect.