Considering the Soho-I has smaller, 30mm drivers (the CL model has 40mm drivers, for example), the headphones sounded better than I thought they would. Harman Kardon's headphones tend to be well-balanced with good clarity and pleasantly plummy bass. The Soho-I headphones are in the same vein but they just aren't as dynamic or rich-sounding. That said, I thought they sounded slightly better than the Bowers & Wilkins P3. The two models offer similar bass performance, but the P3 headphones sound slightly duller (translation: the Soho had a bit more bass definition). However, the P3 headphones are arguably more comfortable to wear and fit those with bigger heads better.
It's also worth noting that the Soho-I headphones don't do a great job of passively sealing out noise. I walked around with them in the streets of New York and they let in quite a bit of sound, so they aren't ideal for noisier environments.
In the end, they sound good, but with the competition so fierce these days in the headphone market, I've come to expect a little more from $200 headphones. So while they exceeded my expectations on a certain level, from a performance standpoint they're not at the same level as the company's larger headphones. (And the CL model is down to $120 online).
When I first saw the Harman Kardon Soho-I headphones, I was excited because I liked their design and was keen to try a higher-performance on-ear headphone that was relatively compact and hopefully comfortable. If that's what you're in the market for, on many levels, the Soho-I headphones deliver, though their styling certainly isn't going to appeal to everyone. If they offered exceptional performance, I'd worry less about the design of their case, but when the sound doesn't blow you away -- it's very good but not excellent, especially for the price -- a poorly designed case bothers you more.
To put it more succinctly, I liked the Soho-I headphones, but I didn't love them -- and I was kind of hoping I would.