Not convinced about the economics of harvesting Helium 3 from the moon.
The fusion reactions with Helium 3 are the best but you can produce it by neutron bombardment from Lithium which strikes me as a much better way than attempting to harvest the very small amounts on the moon
It's only 10 parts per billion!
I think the people who are on for this are really people who are looking for a justification for manned space exploration rather than people with a real financial interest.