I think the name "HHO" itself hints that some amount of bullshit is taking place - the electrolysis units are obviously burning a 2:1 mixture of H2 and O2, not some weird mixture of atomic hydrogen and oxygen or impossible isomer of water. Empirically (via youtube), there is a strong connection between "HHO" promoters and "water-fueled car" and "over-unity generator" fraudsters. Oxyhydrogen torches are pretty awesome - I've used both a small electrolysis unit for jewelry work, and a larger tank-fed torch for working with fused quartz. Amazingly clean and hot flame, with definite niche-applications. However, oxyhydrogen combustion (electrolysis-derived, or otherwise) isn't exactly a revolutionary technology. We've made industrial use of it since the 1860s [1], and the trend has been gradual replacement by other fuels and techniques (TIG, electric arc furnaces, etc) that are more controllable and lack H2's unique shortcomings - eg. hydrogen embrittlement, massive range of explosive concentrations, and incredible ability to diffuse through things.

[1] Faraday's 1861 lecture on platinum-group metals is a great example. Small-scale platinum casting is one of the big uses for oxyhydrogen - the combination of a high melting point and severe carbon embrittlement make H2 ideal for working with platinum.