I think they mdr-1am2 is intended for the portable devices that many people are using for music but, they're not compact, the earcups swivel inwards making them more flat but, they don't fold which probably makes them more durable. They're absurdly light and build quality seems very good, it only has metal were its really necessary, they're nicer than they look in pics. The build seems quite similar to the mdr-m1st studio headphone.
Isolation isn't their strong point, they don't seem to leak much but they let more noise in than some other closed backs I've used. Those got hot quickly though and weren't great for long use. I can wear the mdr-1am2 for a long time with no discomfort or sweaty ears.
I use mine once or twice a week for several hours, I mostly use IEMs. I listen to various types of electronic music, most of it very bassy, they're ideal for it. I was very surprised at the bass power, I don't think there are many decent wired headphones in this price range that can deliver such big bass without extra gear and EQ software. The overall sound is not exactly the same but is like the xba-n3 though more bassy and a little warmer.
I haven't heard the hd569, I imagine that the Sennheiser isolates better. I also use a hd25 with an IFI Go Blu as a very durable lightweight set up for on the go. Its a great sounding headphone, more of an aggressive, in your face type of sound, the bass boost on the Go Blu really improves the fun, its too much with the mdr-1am2.
I have IEMs that need more power than the mdr-1am2 which is generally a good thing but, with some desktop amps it may be tricky to get the volume low enough unless you reduce the source volume. With the HipDac it goes from silent to as loud as I want it with a very short turn of the knob. Its nice to have two cables, I usually only use balanced with things that need the extra power and the mdr-1am2 doesn't need it though I like the chunky 4.4mm plug. I can't say for sure if I've noticed a difference in sound quality with balanced, to test it properly and be sure that a difference isn't just due to slightly increased volume, is a big chore to set up and I don't care enough to bother.