I gotta say guys, having compared both extensively, Fidelio L2 crushes Solo 2 in the bass department. I was going to buy Solo 2 but ended up buying L2. The thing is, L2 is so good that I'm going to sell my Sennheiser HD650. It's not basshead level bass, no, but there's still a lot of quantity and the quality is so good. Sounds amazing with Chord Hugo. Unlike Solo 2, it scales great as well, sounding much better with Hugo than just from headphone jack of phone/tablet.
The sound signature is neutral, but with extra bass that hits strong, clean and beautifully. It is simply better than any portable headphones I've heard. That includes Solo 2, Senn Momentum, B&W P7, Onkyo ES-HF300, AKG K550, Beoplay H6 and some others I don't remember now. I used to like Momentum a lot, but after hearing better headphones, it's overly warm sound signature made me kind of sick. I couldn't stand how yummy everything sounded so I sold them. I've been through some other portable headphones since then, never finding the sound signature I liked. Now that I've found Fidelio L2, I'm going to be keeping them for a very long time. They are semi-open so I believe that helps to make them sound so great.
I like EDM and I've found L2 to be one of the best headphones for EDM. Trance, house, synthpop and all others sound great. It makes you want to dance. L2 has that wow factor, that makes you want to get up and dance. It also sounds great with pop, jazz, rock and all other genres.