Even if you just seed your 200lbs of rock with 15lbs of live rock, it’s absolutely worth it. It’s hard to explain or quantify just how much of a difference real live rock makes. The tank I have no was started with 75% dry rock and 25% live, and now at about 10 months I’m still having issues with nutrients, dry rock just isn’t as porous and so it’s difficult for it to aid in denitrification (nevermind the fact that bottled bacteria just can’t compete with the diversity that comes on live rock). IMO, it’s worth every penny, and is just as important as lighting and flow.All I have ever used was dry rock. Mostly because it is what I had at my disposal, and what was given to me.
But that does not mean that I would not use live rock.
For me, it's the price. I just can't see spending $250 for 15 pounds of rock, especially when I already have over 200# of dry rock now. (yes, I understand most of that is shipping, which further makes my point)