Another grad student / TA checking in … physics, for what it’s worth.
I’m a bit confused by the ‘paid for a full professor’ notion. I’d certainly be pissed if I chose a school that advertised teaching by full professors and then saw primarily TAs but I’ve never seen this. I’m not familiar with 2year colleges, but I know that many 4year colleges use their professor teaching stats as selling points. Schools that utilize TAs may not advertise it, but I’ve never heard of them hiding it, either. And you don’t need a ritzy private school to get professors teaching - many of the smaller state schools focus on undergraduate education as well. I think it’s perfectly reasonable to want professors teaching but I think it’s your responsibility to do the research and pick an appropriate school.
I also hear a lot about the language issue (being one of the few native English speakers). I agree that it’s a problem, but I also think that students tend to use accents as an excuse. My current university requires new TAs from non-English speaking countries to pass a University admistered exam (in addition to TOEFL admissions criteria). This focuses on spoken English and I think this helps somewhat. Most commonly, it’s not a complete language problem as much as a combination of poor attitude towards teaching with slightly broken english. I try to be sympathetic but I also expect the undergrads to make an effort in understanding. These TAs are my colleagues and I interact with them on a regular basis. Some are damn near impossible to understand. Others just require listening a little more carefully - and I think it’s perfectly reasonable (and probably a good life experience) for undergrads to learn to listen. This is also a problem with tenured professors. Most are understandable - but you have to be actively listening to know what they’re saying. There are still a few that flat out don’t speak English. I’ll leave that problem to someone else.
Another issue is the role of the graduate student. Our department structures it such that professors (possibly adjunct) do the lecturing (300-400 students this year - budget cuts!) and TAs are responsible for smaller groups of students. We hold office hours, run lab sessions and group problem solving sessions (discussion / recitation / whatever your favorite word is). With each passing semester, I’m becoming more convinced that noone has ever learned anything in a physics lecture. I don’t think it would make a bit of difference in this size / structure of course if it’s a tenured professor, a graduate student, or someone off the street reading the book outloud. The learning takes place in our small group activities. Overall, ours are quite structured such that the TAs don’t provide much input. It’s really luck of the draw and I don’t think your chances would be any better if it was a group of tenured profs rather than TAs.
Completely anecdotal … The quality of teaching (especially in level 1/2 classes) is most dependent on attitude and enthusiasm. There are enthusiastic grad students and apathetic grad students. These tend to grow up into enthusiastic profs and apathetic profs (where enthusiastic and apathetic are taken to be with regards to teaching).