Working for our family.
Have been using for about two weeks and it is slowly getting better.  My son is a VERY deep sleeper and it is taking a while for him to feel/hear the alarm...but he is starting to sleep a little lighter.  We have learned his night schedule from the alarm, which has helped us wake him at the perfect time before we go to bed.  The only reason I am giving 4 stars out of 5, is that the band is kind of loose for my sons arms, and the clip slips off fairly often (he must be a wild sleeper).  Overall, I do see this helping our family, and for the right price.
Rating: 4 stars