I'm a guitarist and bassist who has spent a lot of time, money and effort buying pedals and amps, stressing about all those details we all stress about. Also a bit of a traditionalist, which is why sometimes the digital revolution depresses me. Thats my background.
Do the amp sims sound good? Yes they really do. The bass amps, the guitar amps, all the amps sound really killer.
Do the effects sound good? Yes. They do. Some people complain about the overdrives but I think they are perfectly good especially in a live context.
The delays and reverbs are really good, especially the delays. The reverbs function well in their contexts, they aren't as "wow" as the other effects but are practical.
Its all good. You can do almost anything with it. Its small. If you understand a bit about gainstaging - making sure that all your digital effects are going into one another with the right volumes etc - you will not be able to tell much difference with real amps and effects.
Having said that, there is something about the live tweakability of effect pedals that make real analog stuff just more fun for me. Also I get attached to the old pedals I had for years and know them pretty well.
I use the HX live for my voice, and for recording bass and guitar. For another band where I play bass, I use it as my entire bass effects unit. Things like stacking multiple Klons and EQ sections are easy and sound cool.
I don't love the power supply, but it isn't terrible. It just could be shaped a bit more stable. With the wrong powerstrip, its sometimes a bit shaky. The solution is bring your own powerstrip for stability at a live show.
I think you can power it with third party power supplies but it gets tricky since it eats a lot of milliamps.