There's circumstantial evidence about his possible cheating, but the real proof would be in the games he played. The people on that site seem to think it would be an inordinate burden to bother to check his games, many of which are published in his book, but don't find any problem accusing him. It would take a dedicated person an afternoon to find out whether his games had a high match-up rate. If they have the book, they will see that de la Maza performed post-game engine analysis on many of his games and published the results in the book. It doesn't look like he cheated, but I haven't gone through and checked his findings.
The book's main problems are:
a) he oversells the benefits of a specific type of tactics training
b) he continues to oversell his concept throughout the book (it's only 126 pages long, and much of the text is extolling the virtues of his snake oil)
c) he himself didn't follow his own advice! He states in several places names of openings, tactics, and analysis that could only have been known if he had not followed his own advice. He clearly studied Kotov in depth.
So in terms of whether his program works, it doesn't matter one iota whether he cheated. His program doesn't work, and that's the main problem.
I don't think he cheated. Look at his USCF player card. It's not like he gained 400 points in 2 tournaments. If he cheated, he did it in a way to make himself look like any other improving player.
Many people have tried his tactics program and seen some success, just not the same success MDLM did because, as was stated earlier in the thread, even MDLM didn't follow his own program.
Read the link, he disagrees on this point.
I have read every post on his blog over the past year. I'm familiar with his arguments. I'm just saying to look at MDLM's USCF tournament card. Why spend all that time and effort over the course of a year to hide the fact you were cheating? To what end? To win a measly $10K? He spent all that time so he could make $2.50/hour? Sounds like a get poor slow plan not worthy of an MIT PhD.