[tw04]

dd-wrt is willing to include closed binaries from router MFGs so they tend to support a larger list of hardware than OpenWRT and on certain models have far better performance. OpenWRT has a massive community supporting it so, in general I'd say they're progressing faster/adding more features.

If you have the luxury of buying new hardware, I would go the OpenWRT route but just make sure you read EVERYTHING on the hardware support page before pulling the trigger. If you're trying to convert an existing router, definitely do research on both, there are advantages to each. Personally if I had a router supported fully by both, I'd go OpenWRT at this point.