Who explains the real problem of Band 4 well?

I worked in Wang Changxi, Spark. Relatively speaking, I think Spark's explanation is better, and the phrases involved in related topics are also explained in detail. Spark's listening CD is rich, with electronic version. You can watch subtitles on P4 P5, which is convenient for listening and watching in bed. But as far as composition is concerned, I think Wang Changxi's is better, because it not only gives two short essays, but also sets out from different angles. On the whole, I think Spark's is better.