I've given out the M50 as a gift several times and every single time it has been a huge hit. I think with gifting audio gear, the end result isn't just predicated on sound quality alone but also on the perception of what they are receiving. In most cases, the people who receive the gift are going to instantly google all they can about what it is that they just got, so imagine their surprise when they see that the ATHM50 is one of if not the most praised and widely accepted "awesome headphones" out there. This also enhances their user experience knowing that they have a headphone so universally praised, so the bias when they listen to music is going to be one of even more satisfaction. This has been my experience with giving them as a gift before. And it doesn't hurt that they have such an engaging and exciting signature. Whereas something like the Brainwavz might come off as sterile sounding and they might just think it's some cheap Asian brand when they google it. Obviously we know that's not the case. For gifting, a certain wow factor I think goes a long way. Either thunderous bass, exxagerated soundstage, or supreme looks/build quality are going to get the attention of people who perhaps aren't audiophiles and they'll enjoy the product more.
Although one time I did gift the M50 and they returned it for some Beats Solos because "I wanted a more known brand and not some brand that no one knows anything about" -__-