I took 2 HX flights this week, which might have been my first ever (I'm not 100% sure). I wasn't too worried about them going under because both were close in bookings.

Following are a few comments:
-I flew from SHA to HKG and returned to PVG
-both flights were on single class A320s
-the SHA-HKG flight was pretty sweet from a convenience standpoint; in fact
-the food was definitely edible (let's call it a midpoint between MU and KA)
-I found the staff to be friendly/professional
-they use PVG S1 (at least for my flight), which I greatly dislike

All in all, they exceeded my expectations, which were admittedly low.