I'll make a disclaimer that I have been sitting at a very low channel count until now.
I like vixen in general when dealing with "strings" since the effects you are building visually correlate to the grid in a logical way. Simple you learn very quickly to correlate visual pattern X to a certain "Squiggle" Y in vixen. However, what I found out when starting to go node based is those squiggles become less and less understandable. For example a mega tree in the traditional sense going in a circle is easy to visualize in vixen. However, going top to bottom (unless you orrentate the channels that way), not so much.
I think it is to early to judge which tool will be better in the long run, but right now LSP with with "layers", makes doing a node based mega tree quite a bit easier.
One thing I've been wondering is if we can go "equation based" (like higher end tools do) for certain complex items (like node based mega trees). As long as people could map their tree to a certain matrix, it would be possible to share equations where you plug in your variables to get certain effects. The cool thing about starting with a mega tree, you can 3d to 2d map to a rectangle.