When they first came out, they released them too early trying to compete with Garret's GTX line. They sourced a cheap manufacturer, and had turbine wheels shooting out of the exhaust very very often. They shut down production, fixed the problem, and came back.
I haven't heard of a lot of people using them, and I believe it's just the stigma from the rushed, first shipment of them. They have some cool tech and ideas. From what I've seen, they claim to flow more than GTX's, but from cars making HP, the GTX's seem to flow more and take more abuse.
Once cool feature is that they come with (or maybe it's just an option) a diverter valve built in. This is a valve that works like a blow off valve, but pushes that air back into your intake before the turbo. This is a really good think if you're got a truck with a MAF, and if not, your only advantage is, it's just quieter than a BOV. The point of having a diverter valve/BOV is that you never get turbo chatter when letting off of WOT, and this allows for the turbo to have thinner shafts, less rotating mass, quicker spools, but doesn't sacrifice durability. You would need to hook it up some way to your throttle input. Probably with an Arduino and come custom code.
Thanks all I know. Hope it helps!
