Do not take Modern Algebra with Professor Siegel if you're someone who's completely new to group theory and the ideas behind it.
Now, part of the reason I struggled in this class was because I didn't really try to understand the material from the get-go, so when it was time to buckle down, I was completely lost. However, that is not to say Professor Siegel tried to make the class easy.
First of all, he graded our midterms with a guessing penalty on the true or false section, meaning that if you got the right answer, you got 2 points, but if you got the wrong answer, you got -3 points. The class was already hard on its own, but this guessing penalty just made it even harder to try to get a decent grade.
Additionally, he tended to introduce new ideas and theorems in the homework without ever going over them in class. However, those same concepts would then show up on the midterms, meaning if you didn't get them on the homework, you were basically on your own.
Finally, he did a really poor job with giving us answer keys for the homework to study. He would either post only part of the solution to the homework problems or blame it on the TAs, though all of the teachers I've had in the past have been good about posting the answer keys at a reasonable time.
Some people liked Professor Siegel - I did not. If you don't want to be stressed out of your mind in this class, don't take it with him.