Iyengar, but rather the proliferation of such practices as Goat Yoga and Beer Yoga. Sticking the word 'yoga' in the name doesn't make it right, in my not-so-humble opinion.
Now, I'm sure that some of the leaders of these classes are teaching with integrity and are genuinely trying to find a way to introduce yoga to as many people as they can. I'm equally sure, though, that for some it's just a kerching move, aimed at separating gullible hipsters from their money.
Twice in the last week I've heard about PiYo (note that annoying upper case Y). This is apparently a fusion of Pilates and yoga and not the latest in pick-your-own veg - although it might as well be. Pilates is a fine practice. It has proved beneficial to many people, including those who also practise yoga. My question is: why the mash-up? Why not teach both, but separately?
It is, as they say where I come from, neither t'other nor which.