Reading about the NEX cameras here has made me regret my purchase.....

Is this post meant to be ironic?   If so you need to be careful as such things don't translate well on the internet, particularly when there is a large community reading who do not have English as a native language

The NEX 6 is not a mediocre camera: it is an excellent rangefinder-style camera which is perfect for travel and street type photography.  The only direct alternatives to the NEX 6 are more expensive options from Fuji or Leica, the Micro four thirds format that suffers from a smaller sensor and which can never support full-frame, or the Samsung NX format which has a nicer lens system than Sony but (currently) inferior bodies.  Neither Canon or Nikon mirrorless systems offer any real competition to NEX for different reasons

A DSLR is an entirely different proposition and can't really be compared to a mirrorless camera any more than a 35mm rangefinder system can be compared to a 35mm SLR system