Nozomu Nozomi is a primarily genderbender manga that stands out from it's peers for several reasons: it's fairly short and to the point, has full colour art throughout and treats it's sexual content in a interesting way.

Story 6/10:
Apart from what can be gleaned from the synopsis the story of NN is very much affected by the length of the series. With only two volumes to work with there isn't much time to go off sidetracks or moments that doesn't move the story forward and NN manages to avoid this to a satisfying degree. My main complaint here is that the ending, like many other shorter genderbender manga, comes fairly abruptly, leaving the reader wanting more and to see what will be become of the characters after all they have gone through in the short span of the story. There is no real structure to the series as such, the stories follows the main character and those around him/her as they deal with the changes that have come upon them. The adult scenes and themes included in the series are handled with surprising maturity and felt like the fit into the story naturally rather than just inserted for fan-service (though there is plenty of that).

Art 7/10:
The art, as mentioned, is in really nicely rendered full colour and the characters have nice and distinct designs. Censorship for the adult scenes is to be expected but doesn't detract from these at all.

Character 6/10:
One of the main problems with NN is that other than the MC, the other characters in the story are not given enough time to be developed. There is no story told from their perspective and for a series that deals quite a bit with mental change this is a big minus for me.
Bonus points for a MC that deals with the changes to his gender without the now cliché over-the-top reactions of the genre.

Enjoyment 8/10:
For me, NN is such a short series that, while what has been said above about the series faults still apply, there is still much enjoyment to get out of it. For someone who likes genderbender I have to admit that NN hit a lot of great buttons for me, concerning the gradual change of the MC in particular.

Overall 7/10:
To me, if you enjoy genderbender manga and don't mind reading a story that doesn't try to be a longer, more in-depth story, NN will hardly be a waste of time. There is enough there to enjoy to cover up for the faults but adjust your expectations accordingly. That being said, I'm sort of getting tired of these shorter series almost always having rushed endings.