Your initial post didn’t describe a specific problem. You merely said you got this router cheap, you do mostly gaming and streaming, and were curious about dd-wrt and thought it might be better. As I said, I don’t think dd-wrt is necessarily going to make improvements in your current circumstances, at least in terms of performance. If that’s your expectation and goal, then throwing dd-wrt or tomato into the mix may prove disappointing.
That said, is dd-wrt better? Yes, in terms of features/functionality. If you find that interesting and want to pursue it on those grounds, by all means, do so. dd-wrt is ABSOLUTELY LOADED w/ features, many even I don’t use. It supports numerous forms of bridging (WDS, client, repeater, both bridged and non-bridged), VPN client and server, SSHD, QoS, USB (when applicable), NAS, captive portals, various logging options, visual bandwidth monitoring, detailed connection monitoring, WOL, VLANs, yada yada. You can even install what’s called optware and add more features beyond what’s already available (e.g., bittorrent client). It’s a networking nerd’s paradise.
As long as you're willing to accept the slight risk of bricking a router, and willing to take the time to learn the new UI and additional features, I’m sure you’ll learn a lot and eventually find things you can employ within your own network. And it’s a lot of fun too!