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While it is true that LACs do not use TAs for teaching, it is not uncommon for upper-level undergraduates to assist in the running of labs as TAs. I have friends at Davidson and Franklin & Marshall who serve in this respect. (This is not a bad thing. For potential grad students, it’s actually a very good thing.)</p>
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If a professor is signed up to teach a class at a university, (s)he does so. It is not acceptable for Professor Jones to be like, “Hey, I don’t feel like teaching today; I’m going to have TA Susie teach.” Usually introductory science courses at universities have multiple sections – some taught by professors, some by postdocs, and some by ABDs. The level of expertise, of course, is not necessarily related to the quality of instruction. </p>
<p>As far as personal attention goes, my science professors generally had to beg students to come to office hours. Whether through arrogance or busyness, most people didn’t go. The ones that did received quite a bit of personal attention and tended to do rather well grade-wise.</p>
<p>In any case, any college will have a mix of good and bad professors. A LAC was one of my top choices back when I was applying to colleges, but it dropped after I found out students despised the only professor there who taught Greek. It’s very easy to select good professors, but it takes a bit of time and effort. I highly recommend connecting with upperclassmen and getting advice when you’re choosing classes.</p>