You might even find the colour screen worse. I haven't used a grayscale one but from what little I've seen of them, they look more contrasty to me.
One thing you do get with the colour Etrexes is much longer battery runtime.
A Legend C and a Dakota.
Bright lowish sun, facing into the sun.
Same conditions but back to the sun - body shading the sun, but screens reflecting bright sky.
Overcast (plus a few raindrops)
One thing I have noticed with the colour Etrexes (partner and I have 4 between us) is that the screen brightness is quite variable - you could get a good one or a very bad one, it's just pot luck, nothing to do with the model. Of the 4 we have, one is much better than the one pictured above, one slightly better, and one much worse.