Calculus III is perceived as significantly easier than Calculus II, with many students expressing relief at the transition. The challenges of Calculus II, particularly with integration, are contrasted with the more straightforward concepts in Calculus III, which often involves three-dimensional topics. There is curiosity about Calculus IV, with some mentioning it includes differential equations. Additionally, comparisons are made between complex analysis and real analysis, with some finding the former easier. Overall, the discussion highlights a common sentiment among students regarding the varying difficulties of calculus courses.