Saying this objectively as a NU’EST fan (so all of you waiting out there to jump at me for saying bad things, sit down.)…
They really cannot measure up to the level BAP is at in terms of recognition in Korea (more into recognition later). As far as I remember (I may be wrong) both of NU’EST’s songs up until now charted higher than EXO’s MAMA, though EXO blew them away in sales (partially because international fans can be included in that).
Part of EXO’s recognition simply came from being from a big company. Both TS and Pledis, however, are around the same ‘size’ and have around the same amount of recognition as I see it. They started on a level playing field, and BAP simply blew the competition out of the water. They did something new to the K-pop world (other groups have done hiphop, such as Block B, but not in the same style) and they rocked it and made a name for themselves. NU’EST, while they did do something new, didn’t do something that caught as much attention in the public eye. Hiphop is a popular genre right now, so it probably brought more people to BAP’s music than are willing to go for something that is still very much K-pop like NU’EST’s music.
Simply on being ‘on par’ with each other. Each of the EXO members individually have tons of talent, Baekhyun and DO’s voices continue to amaze me, Kai and Sehun are amazing dancers, etc. but I have yet to see them working all together and having chemistry quite as well as BAP has shown. For dancing BAP has Zelo and Jongup, singing they have Daehyun and Youngjae who have amazed me just as much, and Yongguk is a flipping genius musically who (honestly) is being wasted on the idol world. NU’EST has several strengths, but nothing nearly as strong as the powerhouse members of the other groups.
And then a tiny part of me is sad that BTOB wasn’t mentioned, LOL. But yeah, take it as you like, but that’s my personal opinion on it.