I opted for the Athearn RTR version in D&RGW paint, naturally!
First off, there are currently no HO plastic loco's for D&RGW which have the correct nose light molded in, sadly. There were only a few RR's with this syle (D&RGW, WP, KCS and FEC sort of), so plastic models don't come with them. So to get it right, you'll have to take a file to the nose and carefully modify it for the Details West part. Notice that the nose part includes a chevron shaped bottom piece to help simulate the slant below the gyra light. I have NEVER seen this part look decent on a model, never. IMHO, this needs to be cut off. Just carefully file the slant yourself below the flat spot where you glue the DW part on. Drill holes in the part and add lenses.
I have been following the discussion on the Yahoo Groups email list, and yes, the Athearn has been described as more accurate barring the usual noselight being needed. The Athearn has the correct anticlimber and mailbox battery box detail - which the P2k model lacks. People have had issues with the P2k SD60/50 truck side frames and running speed. There are given pro's and con's to each model in general - the P2k does have a few extra details that the Athearn model doesn't have - so there is some trade off either way.
I bought my first Athearn SD50 just a few weeks ago and it is a lovely model - very nice looking. The major mods needed to make it more D&RGW correct is to change out the snow plow for a taller one, and add the nose gyra light. There may be a few other smaller details but that would get you most of the way there. I'm not anti proto 2000, as I love the GP30 and GP60, but the SD45's and SD50's I go with KATO and Athearn respectively.
Oh yeah, the orange on the Athearn is excellent - to me it is very close in color. Orange color is subjective to lighting etc, but I feel like the orange used on the following all look very good - KATO SD45, Athearn SD40T-2, Athearn GP40-2. The Proto 2000 GP30 and GP60 are slightly darker but also very good.
OTOH, The Proto 2000 SD7, SD9, and SD45 are all a darker more red orange which I don't care for. I did buy the SD9's though.