Having had some time to look at MH clusters, I think they will be useful, but limited by the relatively narrow band of cMs they've chosen. This may well be because of the size of files generated by using wider limits, say, 20-400 cMs, may be just too great to email. I may be wrong? Significant matches do occur even below 15, although possibly beyond the scope of most family trees, without which detailed info we're struggling.
I'll be interested to see how MH develops this tool...