The OCR Theory paper is extremely easy, Simple DNS, Database theory, Hardware, CPU, etc.
The A452 / A453 Controlled Assessments are quite a challenge however and at first glance look quite simple, however they are always a lot harder. Saying this, the Controlled Assessment doesn't require 20 hours worth of work, I did my A453 in about 5, and got 42/45 marks resulting in an A*
If anyone would like a look at some material from the course, whether it be work of my own regarding the theory, example response to the ca, just let me know.