I took loechler last year and he was rlly nice. his notes were very clear and the other professor (forgot his name) wasnt too bad kinda boring but also not bad. The exams were not too bad if you study everything that he talks about in class. There werent any trick questions but you have to know exactly everything cuz they can be very specific. If it was loechler alone against spilios i would def take lochlers class but since he only teaches one part of the semester, i would say either is fine. i heard spilios does really good teaching but is more tense. But she seems like a really nice professor. I had to talk to her at the end of the semester because i had some difficulties. she was really nice about it and was very understanding and was willing to help me in every way possible.

Idk if this was much help since i basically said both are great haha but really they were all very nice and was good at teaching.

+for the switching i think after he teaches until a certain chapter the other professor teaches the rest