The best way to see if you like them would be to try them out. I owned a pair of m50s... if you never owned a decent pair of headphones before you would probably like them. If you have a place like Guitar Center or Best Buy near by be sure to at least try the m50s along with other similarly priced cans and see which one you like best. They have that fun "v shaped" sound signature with emphasis on the low end and treble and are VERY forward sounding. The soundstage is also quite small and I found myself not enjoying music (especially classic rock) a lot of the time because of this along with its powerful/harsh sound. Build quality is top notch and they would last you for years to come. They do have a good amount of clamping force and comfort isn't the best either. They use pleather pads and since it's a closed back design they can become hot and sweaty after a while of listening, which causes the soft pleather pads to harden in a short amount of time. The headband padding is also rather poor and left me with a hotspot on the middle of my head. During longer listening sessions I could feel the metal headband clamping into my skull. This can be alleviated by adding further padding and stretching the headband. However since it is not that comfortable and the soundstage is poor, I wouldn't recommend them in general for gaming. YMMV. $75 for the original m50s is a decent deal.
The m50x is a slightly tweaked pair of m50s with a removable cable. The sound is more detailed and neutral, however they sound very similar to the m50s. Considering there are other similarly priced headphones like the DT 770 PRO which can do everything better than the m50x for the same price I would not buy them.