I'm not sure if it's at all similar, but after all the Bose bashing on this forum I had the opportunity to give a proper audition to a regular AE2 last year. My first impression was good as I though they were comfortable, but then I started pumping music through them. In a nutshell, they sounded like full-sized iBuds to me: congested and wholly middling to headphones at less than half the price.
Between the D2000 and K550, it comes down to preference. If you're looking for fun, go with the D2000 with its embellished sub-bass and overall smoother/looser/forgiving presentation. If you're looking for more neutrality/accuracy, plunk down the cash for the better resolving/faster/tighter K550. I personally prefer the latter after achieving
the elusive seal, but there are many that would choose the properties of the former. Also, take into account the level of isolation you require. I can listen to my K550 at my normal volume with the woman on the couch right next to me without her hearing a note whereas the D2000 isn't a sealed headphone. (but I personally found them to isolate a bit better than they're said to by many here...)