I'm surprised how many people dismiss this completely when it's obvious they haven't even read the abstracts/intros to the various papers.
There is no claim of anything related to cold fusion - hydrinos as predicted are atomic state with the electron in a lower energy orbitsphere - nothing nuclear/fusion-related.
As for a scam - that implies deliberate intent to defraud and writing a dense 1600-page 3 volume Grand Unified Theory is not the easiest way to go about this. A standard sales letter would be much easier. Plus they are not asking for big money - at least not beyond the $50 million start up capital. It's clear Mills believes his theory is true.
And there are lots of reasons to believe it - mostly the astonishing array of measurable quantities that can be derived from the theory in closed form - things QM will never be capable of. You can't invent this stuff - the formulas for particle mass ratios in terms of fine structure constant only.
Think about electrons - which seems more plausible, a point charge that has a finite probability of being anywhere and everywhere in the universe, or a fluid-like disc of charge, that in the presence of a proton bends into a spinning charge shell in a sphere around it?
The ground state argument, that if there were a lower state then most matter would already be there doesn't make sense - the ground state is stable also. Presumably the equilibrium between the states depends on the local circumstances. Given the trouble Mills seems to have had in creating hydrino-producing prototypes, it's not like falling off a log.
The primary experimental evidence seems to be the anomalous line broadening in H spectra as well as the calorimetry experiments that produce significant excess heat - not just a few degrees - the latest stuff gets up to 700 degrees in 35 seconds. It also predicted the accelerating expansion of the universe which seems to be gaining experimental support, although early days, and the mass of the top quark before it was measured.
As for the math - the published critique by Rathke itself contained a sign error which in my opinion suggests it was a fast hatchet job designed to stifle debate rather than a serious challenge. Mills has responded to Rathke.
Many critiques are insufficiently detailed to be refutable - stuff like "whole thing is nonsense" and so on.
QM didn't make much sense to me when I got my bachelors in physics 35 years ago, although I could parrot enough to get by, but now hydrino theory seems obvious, elegant, simple, powerful and so on... all the things you want a good theory to be.
