Paweł Nowicki recording First In Flight for vibraphone and string quartet. We tried three different sets of sticks today, hard, soft, and medium, and ended up choosing the hard set. They carried a unique brilliance and definition of the sound and provided a nice contrast against the strings.
http://www.dosiamckay.com/stringquartet.shtml
http://www.dosiamckay.com/music/firstinflight.shtml