I just tried the Audeze LCD-2, LCD-3 and the HiFiMan HE560 listening to music for just less than an hour - I got out of work late and the store was closing which kept my listening session limited between these three headphones through a McIntosh Headphone Amp 100. All of these are Open Planar Headphones.
Keep in mind this was a limited listening session, which i would have auditioned for a longer time if time permitted. I found that the LCD-2 was OK sounding with good bass, but sounded more closed in than the LCD 3. The LCD 3 had a wider soundstage of them all, which I found undesirable. I found the bass was less than that compared to the LCD 2. I find if I put my hands over the open planars on the LCD 3, it closed the sound stage, making the headphones sound better.
I found the HiFiMan HE560 needed more volume, which would require a headphone amp. I did not spend as much time on these compared to the LCD-2 and 3, so I don't exactly remember how it sounded and its comparisons.
Note that I found that all the headphones to feel comfortable on my ears in my limited listening session.
I can say that between these three vs. the Grado GS1000e, I found the open plannars sounding dull compared to the Grado. I own the GS1000e, which does not have that much bass as what others have said here. Note, I do not own a headphone amp at this time. The treble and the details that the Grados offer are much preferred over the plannars I auditioned.
I also find the Grado GS1000e very easy to wear, and are non-fatiguing, as I have worn them for a few hours in a few listening session I have had - the Grados are a week old in my possession, and I love them since breaking them in this past week.
I still look forward will still audition these three plannars, to find a backup reference headphone to the Grados. I may look to the PS1000 alternative as I would love to hear these headphones to experience the rave and passion that everyone has for these headphones.