I don't believe in burn in either mate, the thing is i have two pairs of MH1C beside me that tell me otherwise. One is unused the other has ~50 hours on it and they sound very different. I am not talking about mental burn in, they actually do sound different. The burned in pair has allot less bass quantity, a tighter bass, better instrument separation, more pronounced mids, and more detailed treble.
I tend to change between phones as well, and my initial reaction was similar to yours (what where they smoking basically ), but now they actually sound respectable (actually amazing for their price) when i go back to them from a 150-200$ IEM.