I was thinking along the same lines as Snoozeman. The first group CC cruise would have saved me a little bit, but less than $50 total, for what to me was a lesser room. this was 3 years ago, so I booked on my own.
The last two years I could book ES cheaper than the group rate, so never signed up with the group. I felt like a traitor, but I just am not paying a higher rate to be part of the group. They got a 4B price with $75 OBC for the cabin I believe. I took the midship deck 8, 1A, larger than the 4B and higher deck and overall, even counting the OBC, my price direct was still less than the group rate.
Some groups have activities they add into the price, making it even higher yet.
If you are a smart experienced cruise shopper, you can do better on your own. Last year on the group cruise, I got a last minute price drop to $379 from $429, and those who booked the group rate got nadda.