It's been nearly three months since the release of the ETQW 1.5 Beta, and though the update hasn't been officially released, there's now a devblog post that details the changes in 1.5. I'd say the beta stage is nearing its end.

Meanwhile, the maps from the flash-based version of Valve's extremely popular Portal puzzle game have been ported to an unofficial map pack for the retail game. I've personally played through several user-created Portal maps, & a few of them are excellent additions.