Hi Rwilis!
I always enjoy using MetaBox, and I got a little suggestion for you - it would be great if you could implement a small feature for the cloneable fields, as many users want them to be in a specific order.
This is actually really easy to handle, with adding a small jQuery: $('.rwmb-clone').parent().sortable();
The only thing to be implemented would be an additional information at the definition of 'clone' => true to be set to 'sortable' => true, and adding a class to the clone-field holder, or with my function above, as well as some small CSS issues like the sort Icon.
I already testet it even with the Groupfield, everything works just fine!
Have a nice day,
fischi