DD-WRT bricked my router, but I was able to recover it and went tomato instead. Really all I wanted at the time was bandwidth metering when Comcast started enforcing a 250 GB limit.
I thought for sure I was going to brick mine during the initial flashing process, it was pretty complicated, but it worked out and I've had nary a problem with it since. Even upgraded it a few times, which was much simpler. I use it as a wireless bridge so that I can just do wired to my desktop and put the router (which essentially acts as my wireless card) anywhere I want.
You actually download enough to worry about Comcast's cap?