Pros: Comfort, Bass, Unique design?
Cons: Too much bass?
BASS BASS BASS!!!
If you're looking for that open spacious "open-back headphone" sound but you aren't willing to give up the "closed-back" sounding bass, AND you're on a budget... look no further, the ma500s are what you're looking for!
Design: The ma500 has a special design to it, as the drivers swivel independently from the ear-cup chassis. It is suspended in the centre of the earcup by what seems to be rubber. Anyways I believe the purpose for this is so that sound hits your ear at an angle, for a more natural sound. And rather than have a fixed angle like what many other headphones do, this one can be like a custom fit for anyone's ears.
Comfort: These are one of the most comfortable pair of headphones I have had the pleasure of listening to, I can wear them for hours! But due to the rubber surrounding the drivers, it does trap some of the heat from radiating away so they will get warmer than what you might expect something open-back to get.
Sound: Bass might be overpowering for some. It almost sounds like the Philips X2s (solely in the Bass aspect), except X2's bass was slightly more controlled and had more impact(kick?) while not muddying up the mid-range. Also compared to the hd650, they have very similar bass and sub bass, but the ma500 has a bit more of both, it is however not as natural sounding as the 650s. Keep in mind these are about a third of the price of the X2s and 650s. For the price, the ma500 is pretty good. The soundstage is about average for an open-back, the mids and highs as well. Basically the jewels of these are in the bass Department.
The Sony MDR-MA500 is great for kicking back with some bass heavy music/ EDM/ Ambient, but if you want to hear clear transparent vocals, these are probably not the headphones you're looking for.
Thanks for reading and happy listening!!! :D