It really comes down to your volume. If you buy a lot of auction names there and/or have a large portfolio, it may be better to renew DDC. You have to do the math of DDC divided by domain count plus DDC registration cost and compare that to the competitor's registration cost. For me it was about even and the final consideration was just my disgust at the pricing models and Afternic percentages and I just don't want to support all that any more than necessary.
Personally, after many, many years, I moved all my names to Dynadot. Just transferred out the last one today.