I really think Valve should step in and distribute some of the best maps officially. I can't help but think most people just don't want to sit and download some map they're not sure is any good. Not to mention the server's bandwidth is better spent serving the game and not the content.
I've started actively searching for custom map servers instead of just playing the servers in my favorites list and it's depressingly hard to find any of the great custom maps I've recently had the rare pleasure of playing on. And if you do it's an empty server. I've talked to server ops who say custom maps usually kill their server. For whatever reason no one shows up to get a game going.
If Valve could collect some of the best maps into regular map packs as part of an update, then everyone would be guaranteed to have the map. Unfortunately there are loads of legal/authorship/contact hassles which would probably prevent such a thing. Though I'm sure a lot of mappers would love to have their maps featured without any compensation just for the exposure. Some of the maps I've played are definitely worth the consideration. A better distribution system is needed.