Hmm, I'm not familiar with Louis Armstrong's version, but I can imagine it being very appealing, with the roughness of the voice in contrast to Bing's celebrated smoothness. I've sung harmonies to it, and to the one about Walking in a Winter Wonderland, and I know a lovely version of Rudolph which I've done as a duet several times, great offbeat little harmonies, so I am usually willing to listen to those, and hum along my harmonies.