I just got a chance to use Vocal Align. I was working on a song with pretty tight backup vocal phrasing and one part had slightly longer note durations in places. I put the region on the long one and used the short one for the guide @ around 25% and it tightened things up nicely. Pretty cool.

Yes, it's definitely a popular feature, although a lot of people won't understand what they're missing until they use it. For me the biggest deal is tightening up beginnings and particularly, ends of vocals. I used to do that manually and it worked, but it sure took a lot longer.