A London primary school obtained funding to determine the health benefits of Manuka honey over regular honey. Unsurprisingly there were no discernable benefits from ingesting the stuff.
The following is a typical retailer claiming their product contains guaranteed amounts of methylglyoxal but no clear indication of why this is important. The product is significantly more expensive than the average honey product.
Their product is scientifically proven to contain methylglyoxal but the wikipedia page doesn’t seem to promote any health benefit: