Manish valecha or dinesh madan

Both the books are good. it depends on which type of book you want. manish valecha is more exam oriented as it gives tricks to remember the material. 

Module is better then both ...

if it is necessary to make a choice then dinesh madaan is far better then valecha

Institute Study Material is the best for ISCA. Manish Valeccha is similar to SM but, presented colorfully and point wise. However, i prefer preparing from Study Material along with Dinesh Madan.