I would also recommend that you check e-gmat.com out. I finished it last year (26th December) and have since seen significant improvement in my accuracy (75%-85%). I am a lot more confident while answering the questions and look forward to getting new questions every day on the forum. While it is not a book, their audio visual mode of presentation is much more detailed and is designed for non-native speakers (even Germans like me). It also has quite a few questions (they claim 450) and they provide great expert support. I personally have found it very easy to understand. There are others who have praised it in the past for SC (just search the forum). At 30 euros, it is a bargain.
I am not a very fast reader and it usually takes me 1-2 weeks for properly read a 200 page book, however I was able to finish the e-gmat course in 2 weeks while devoting only 2 hrs per day. I probably answered close to 200 questions during this time. I still have quite a few more questions left (in exercises) that I intend to practice before the exam. Just for comparison, I also read the powerscore CR book during that time (an excellent resource for CR, highly recommended), however I probably had to spend 4-5 hrs every day to complete the book. An while this has helped me a lot in CR, I believe that I would need to re-read the some portions of the book again just to recall everything.