When they were the only game in town, they were worth it. Even though they were a pain in the support hand, since they used up so much room on the forearm they left little room, and tended to beat up the support hand in recoil too (at beat they beat up mine).
Now, with quality rail mounted weapon lights like Streamlight's TLR-1 available - no, I don't think they're worth it.
Mindset - Skillset - Toolset. In that order!
Attitude and skill will get you through times of no gear, better than gear will get you through times of no attitude and no skill.