I wouldnt say so :) I heard the UM3x's out of an iPod Shuffle 4g of all DAPs and was quite impressed by its performance. Looks like you're excited to buy your IEMs.
Most people with problems with the UM3x have the older non-detachable version of it from what i've read so far.
I must say you won't go wrong with the SE535 or UM3x. All the best if you're gonna cash it in immediately :) it's still best to audition first though
I'm about to "pull the trigger" for the UM3x, but, there remains a problem..
I use an iPod classic 160GB, and its impedance rating is 32 Ohms, however the Westone UM3x has an impedance of 56 Ohms. Would that make a difference to the sound quality, and the durability of the drivers of the UM3x?