Cata is the first Beta of a videogame I've helped test. I started a few weeks ago, while Vash, Hyjal, Gilneas, and the Worgen starting zone were playable, but Uldum and Twighlight Highlands had no quests and the Goblins were disabled due to some bugs.
My first impression after copying over my main and flying over all the new zones was that Bliz would be lucky to be able launch Cata by the end of 2010. Uldum and Twighlight Highlands both felt massive, almost as big as all of Northrend, and with no quests in place yet, and lots of bugs elsewhere in the game, it felt like it would take a miracle to have the game production ready b/f 2011.
Of course what I had no data points on yet was the rate of development, which people who have been in the beta since it first started, along with the F&F Alpha, have a much better sense of. After the most recent patch that opened the level cap to 85 and filled in the quests in Uldum and TH, it feels much more on pace.
Sill it's clearly an immensely complex undertaking, and I imagine Bliz devs will be working overtime the next few months to finish it and get it launch/production-ready.
What were your impressions of your first ever Beta, and how did they mature as you got more experience testing unfinished games?