Comparison of miniblog with enchanting, BYOB and scratch

Anyone have experience with the miniblog software which is available for Sparki and also have experience/knowledge of other similar software such as

   Enchanting (used with Lego MIndstorm)


   Build your own blocks/BYOB now called Snap


I am interested in the relative power of miniblog to these other products. Of specific interest is the ability to create your own custom blocks.

this was planned for the future of miniblog - beyond 0.81. Release 0.82 is just now coming out but it is not clear whether such has been implemented or not.