course selection

So I decided to start out with 4 courses and drop 1 in October. Almost certainly I will drop one of these two:

Analysis and Probability I (lots of measure theory)	Stochastic Processes I
my officemates (new PhD students) are there this year; plus math PhD students.	lots of Finance Master's students; few PhD students.
course is required, and I can take a qual on this topic.	not required, but I couldn't forgive myself if I didn't learn this stuff! However, I cannot take a qual on this topic.
topic is very theoretical, but essential background for talking to a large set of statisticians.	topic is excellent; very useful.
this year the instructor is very very good (Karatzas).	this year the instructor is ok.
posts LaTeX'd notes and homeworks on the class website	we are following Lawler very closely.
would require quite a bit of focused work, as I'm lagging behind my classmates in terms of math background. Homework is not graded, and 100% of the grade is based on exams (unheard of for me!)	would require relatively little work, except for the apparent requirement of frequent assignments.

I would really rather take it easy my first semester (taking 3+ courses can be bad for my health), but I also really want to take Probability now.