In some cases, I find the nightcore remixes far more pleasant (and somehow better done) than the original...e.g. La Di Da.
The original has waaaay too much obvious autotune, and kind of drags on. The nightcore treatment makes the autotune far less apparent, and reduces it to a more acceptable duration.
Of course, for every 'good' nightcore, there are 20-2000 awful ones...