I'm several weeks into the super-sized class this semester. Mostly, I find it's going fine -- indeed, there are some advantages, I'm finding, to the larger class size.
1) Student participation. While I'm sure the fraction of students attending is probably about the same, with a bigger class, the room actually feels full. And, when I ask a question, there are more students who will answer. I think the interactive aspect of the class is much higher this year. (Related bonus: sounds like more laughing when I tell a joke.)
2) More creativity. This is mostly due to my teaching staff. With a larger teaching staff, we've optimized our resources a bit (e.g.: not every TA teaches a section every week, freeing them to do other things; one-person jobs like prepping section notes have to be done less frequently per person). So now we have special post-homework-go-over-the-problems sections, a new Web site, and Piazza. Thanks team.
The advantages, so far, outweigh the downsides.
1) Grading. I historically grade the first programming assignment on my own, and help grade the midterm/final. I haven't had to do any of that yet. I'm not looking forward to it...
2) Student interest. More students want to meet with me, have lunch, and so on than in previous years. Normally, I would put this in the positive column. But since the semester started I've been soooo busy that I just end up feeling guilty telling students yes... but later in the semester.
I'm curious to see if the increase in students will hold for next year. But if it does I think I can find the positive.