Although I love d'addarios for electric bass, I was really disappointed with the Helicore hybrid on DB. They sounded great initially (although not the easiest arco) but "died" fairly quickly.
I replaced them with Corellis based on Bob Gollihur's website recommendation. They're light and easy on the hands - I agree with Bassworms comments about playability. I don't find them bassy or "rich and growly" though. Perhaps Bassworm's pickup, amp or set-up is better than mine! They'll do for now, but I won't be buying more!