Cady was right.
Con Law: Chemerinsky . It is certainly long, but it's also comprehensive; you won't need to read the whole thing for what you cover in your class. I used the Evidence E&E and thought it was good.
Don't get the Evidence E&E. The rules of evidence are pretty intricate, and the E&E gives them shallow treatment. Moreover, it does not do a good job differentiating various parts of a given rule. I found the information in it helpful for maybe 10% of the class. My evidence professor last semester had us purchase the following: "COURTROOM EVIDENCE HANDBOOK: 2008-2009 Student Edition" by Steven Goode & Olin Guy Wellborn III. This softcover book was extremely helpful as I made my way through the course. The book has a section devoted to each rule, it starts out with an explanation of a given rules "scope & purpose", and it also provides excerpts from case law applying the rule. I'd go with that instead. Besides, your school's library likely has a copy of the Evidence E&E if you want to occasionally refer to it.
The details in all of the E&Es come in the questions and answers; it may not be the case for you (as there usually are legitimate grounds for this complaint with most supplements), but often when people make this complaint about an E&E it's because they focus on the text, not the questions. It's true with pretty much all supplements, though, that they don't go into as much detail as you will in class. Since I generally used supplements to get the big picture and rely on class/other student's outlines for the minutiae, I found it very helpful. I suppose it depends what you're looking for.