So just to update here... In the end, I didn't end up getting the K271's for my sister, mostly because when I actually saw their size in person, they were pushing the limits of what a 21-year old female would consider portable. So I ended up getting her a pair of Shure SRH440's instead, which she was very happy with and I actually liked the sound of.
That being said, it seemed like a great opportunity to buy a pair of K271's for myself instead. I brought them into the office because I think people sitting next to me have gotten tired of hearing my music from Grados by now. These were some of my quick thoughts:
* To be fair, a couple of things to note. The first is that the new headphones probably only have 20-30 hours of burn in so far, whereas the Grados at the office have hundreds of hours. Also, important to note that I've been using SR-325i's at work (I keep the RS-2's at home). I know that many people, even Grado lovers, find the 325's as too tinny, too sharp--clarity without the warmth. Comparing them with my SR-125's at home may be a closer match.
Setup @ work: Desktop -> iTunes -> Apple Lossless Music Files -> Creative Audigy Platinum Box 1/4" -> AKG K271 MK II
There have been a number of K271 appreciation threads on here, so just to focus on their similarities to Grados, I was pretty surprised (in a good way) at the comparison. Clearly the focus on the range is fairly close. I feel like these focus a bit more on the mids and a little less on the highs then the Grados I own, lacking the same degree of balance, but the clarity is definitely there. It is still a bright sound. Bass strikes me as extremely similar (very subdued).
There is a muffled quality to the close-backed headphones that I'm still getting used to--maybe the burn in will help over time. They did well with 38 Special, the Eagles, Alabama or Kansas. Did okay with Goldfinger, Van Halen or Led Zeppelin. I think they underperformed the Grados in the classical arena. They struggled a bit with harder rock like Metallica or Ozzy, sounding a bit more muddled in the low end.
Overall I'm happy for with them for an at-work option where open-backed headphones can cause some intra-office friction. I'm thinking of upgrading the cable to a Headphile cable instead. It seemed like some reviews were saying it was a nice improvement.
Edited by tjcaine - 1/3/14 at 1:59pm