First off, the genre listed for this song is completely wrong.. this isn't metal.. It's Alternative Rock with some Post-Grunge qualities to it.
Vocals-wise, its just a great and very fun tune. On a setlist it works well as a nice break for the drummer/bassist as their sections are limited in comparison to the lead guitarist/vocals. The Harmonies are fun as well with its playful melody if you have a large group of people chances are they'll all join in at the start of the song.
Not too much of a vocal challenge as there aren't too many octave changes and the melody doesn't change too terribly much, but fun none-the-less.