Ok, just my 2 cents worth:

First, I build sub-250 gram quads which means smaller, T-Mount, motors. The
5mm shaft motors seem to be heavier than a T-Mount equivent. Weight is the
primary consideration; 15-17 grams is about tops and 20 grams is absolute max
and requires compromising other componenets. Consequently, a 2004 is pretty
much at the top for me. I mostly use motors from 1103 to 1504.5. 
Heavy motors are just not an option for me. 

Now, give me a good T-Mount 2004 motor that comes in at 15 grams with wires 
and we are talking. Weight matters. This is what we need...lighter motors that
are powerful and efficient. 

Yeah, my builds tend to be a bit "Frankenstienish" and rarely look "pretty". 
As long as the thing flys fine, then it works for me. Besides, next week I may
have different motors on the thing anyway. 

I rarely care about motor color...or any other color for that matter as it is totally
irrelevant on something that can't be seen. I guess that is just me 


As for seeing the quad in the sky; are you kidding? My quads are barely visible when
in the air...much less the motors. Have you ever tried to track a sub-250 gram quad 
at an altitude of over 350 feet (over 100 meters) ?? Also, ever try to track a quad that
is moving fast regardless of altitude. I put money on it, that you can't tell the motor
color when the quad is in flight. 

Additionally, I am working to be stealthy...not seen, not heard, out of sight, out of mind,
and under the radar. I have even moved to remote or isolated areas to fly where there
are NO people. So, who will see. If I didn't post pictures, no one would know what my
quads looked like. 

Finding a downed quad...yeah, color hasn't helped me much yet. I think that I would
use some type of flourescent tape or paint on the quad itself rather than rely on motor
color. In fact, the quad is usually upside after a crash and you can't see the motors
anyway. 

On the one hand, I like the idea of using a flashlight at night if you can't find it during 
the day. On the other hand, night searches where I fly might be kind of sketchy to 
say the least.

That said, I like the white wires and think that white motors are pretty cool. I also
like the shiny gold and silver motors; then there is basic black. If I was looking for
color, I would stay with the more neutral colors that would go with any other color
scheme; yeah: white, black, gold, silver, maybe even gray or gun metal blue.