Bristle Worms...Good or Bad?

[MMAX]

I'm in the process of tearing down a 20gal and transferring some of the stuff into my 100. One problem...I have several large bristle worms living in the 20. By several I mean a whole hell of a lot of them. What should I expect when I add some bristle worm infested live rock from my 20 into the 100? I've heard they are good for the sand bed and are a sign of a healthy, established tank but they're nasty none the less.