Funny, I don't recall mentioning them being "Pro" quality, just particularly good for the slim, portable device thats pumping out the sound and it is good for what it is. In my domestic environment I'm impressed with the sound it produces for the components its has.
It's never going to replace a quality HiFi setup, but it's not supposed to. Dear god I've spent tens of thousands on HiFi gear over the years, I wouldn't trade my Arcam rig for an iPad for audio, that's just ludicrous and I don't think anyone would suggest otherwise. But the iPad certainly could cope well as a sole audio source, for say, a student living in a small flat or something along those lines.