I spent some time listening to the TH600s and TH900s and think I fell in love with the TH600s. I need to demo them properly, but was really impressed.
Other than that almost all my time was spent chatting with folks on the Noisy Motel stand, explaining that I'm not an employee so don't know prices and constantly asking Billy how much stuff costs so I could tell them. It was fun, but a bit challenging when some guy tried to bargain with me and didn't get that I don't work there!
As for hiss on the wooden amp, it was dead silent with the Miracles which are almost the most sensitive IEMs I've owned.
Regarding the Miracles, you said you like the extra bass of the AX-60s so I think you'd prefer the JH13s (from what I've been told about them) because they've got a little more bass and are also apparently more accurate than the Miracles. The local UM service is appalling so I'd recommend anything but their IEMs if there are others that suit. You could order through an overseas supplier though I suppose.
Worst customer service ever!
Finally answered one of my 20 emails after 2 months... Even if UM makes the best IEM I wouldn't buy it unless they up their game in the CS department. It was a complete nightmare and they sent me a tracking number after my Miracles arrived. There was also no signature and they just left it at my door where anybody could have taken them.