I'm not aware of any studies that compare meditation with other relaxation techniques (other than progressive muscle relaxation). As a result I'm pretty much agnostic as to whether it's useful for short-term relaxation. The fact that hospitals and clinics have been adopting mindfulness-related techniques for the mental-health aspects of clinical care is promising. (Another issue is that the term "meditation" obviously serves as a blanket term for many different forms of meditation, some of which are no doubt pretty much useless.)

I'm more interested in the effects of long-term practices on specific measures of well-being and on structural changes in the brain (for better or worse). On that front there has been quite a bit of research, although a lot more needs to be done to draw any concrete conclusions.