Yes, that's the link.
Well, DD-WRT has many more options, which allow for some pretty advanced setups. I also found it much more capable of handling high loads (large number of connections) than the stock firmware.
I tested with one desktop and two laptops (wireless n and g) downloading torrents with thousands of seeders at the same time and I observed no problems with disconnects or stuff like that, which I experienced when using stock firmware.
On my D1, with stock firmware 4.00 it was practically unusable, until I upgraded to 4.11, which was a lot more stable, but still had problems. Sorry to see D-Link putting out such ****py firmware.
DD-WRT is based on the Linux kernel and it has a place in the interface where you can execute Linux commands directly. You can also connect over SSH or telnet if you enable those.
You can enable logging and have the logs sent to an external server (space restrictions, the router only has 4MB). I also find the CPU and memory usage estimations useful.
One thing I miss in BrainSlayer's builds is OpenVPN, which other more complete DD-WRT builds have. But this, just like the logging, is missing due to space restrictions. It's more suitable for routers with 8MB ROMs. There is a way to get it via a lot of manual work, but I haven't gotten to it yet.
Case in point, I find DD-WRT a lot more powerful, stable and flexible. You can make an idea of what features to expect by checking out http://dd-wrt.com/demo/