To me the 10s are very bass heavy. Some have even stated that it's like attaching a subwoofer to ears. The esw9 is musical and warm but has no where near the detail as the esw9ltd. Actually my esw9 is religated to just sitting on a shelf waiting for a beach day in the summer. I've owned the es10' esw10jpn,esw11ltd,esw9, and the esw9ltd all at the same time and done extensive comparing. It is obvious to my ears that the esw9 is older technology sounding a bit dull and smeared but it is still fun if it's all you have and a pretty good bargain for lower budgets.
Edit add-At this point my two most used portables are the esw11ltd and the esw9ltd. I sold the es10s, I was always very unimpressed with their sound. Although the big drivers gave a fullness, they felt very clostriphobic. The esw11ltd has a more open airy while still keeping good bass and fullness with the 53mm drivers as well. The esw10jpn is more of the collectable, less were made and they have a distinctive sound and ultra detail. I use them on occasion when I want to really listen carefully but I'm a little jumpy wearing them out because they are somewhat irreplaceable. The esw9ltd seems to be a halfway ground between the esw9 and the esw10jpn, leaning a step or two closer to the esw10jpn.