The technique has been applied more for lagers than ales but it works for both. Supposedly 7psi is typical of the pressures in a large fermentor anyway, and 15psi is the limit above which yeast health starts to suffer. Not sure that means the yeast start producing bad stuff though.
The lowered krausen is really a non-issue, you still have to have some head space above your wort to avoid blowoff and blowoff into your spunding valve does cause clogs. I haven't really seen a significantly faster fermentation rate, it may get done a little faster but the yeast still have to drop clear and that time isn't accelerated by pressure. The free carbonation is a slight benefit over what you get with conventional ferms, I haven't been dialing the pressure up to 30psi to take full advantage. With an ale its tricky to time this, with a lager The O2-free environment/transfers are probably a bigger benefit than anything else. Thats what attracted me. I've been troubleshooting my malt-forward beers that don't seem to have quite the flavor they could, and I hypothesized that oxidation was a culprit (after getting my water chemistry in order). I still haven't concluded anything for sure (have to keep hoppy brews in the rotation) but I've made a few pretty tasty malty beers now so I've been sticking with it. All in all, I am not seeing a huge difference but its no more difficult so I am doing it on the conical just to allow me to live with slightly higher ferm temps.
All in all its an interesting technique to play with but it doesn't seem to be head and shoulders above conventional methods.