I thought they were interesting at first but grew disenchanted as it seems like they don't really know what they are doing. Trevor understands in broad strokes what he wants to do, but when it gets down to the nuts and bolts of it they seem lost and rather hearing about milestones it's a never ending list of so called partnerships.... relationships really that just end up obscuring their exact function and value. Polymath continues to become more and more niche when you consider the original road map.
I think the market they are going after is promising, but I don't see Polymath as a big leader. If the development was promising and all signs indicated they were going to be a major ecosystem, institutional investors would be all in already and this would be around EOS levels. There's probably good reason they are fading slowly into obscurity, I'm guessing its because they haven't really innovated and shown how they are necessary at all. More likely than not they will be entirely replaced and out worked when accommodating regulations pass and opportunity opens up.