WJEC is an excellent exam board, or at least, it was when I took my GCSEs and A-Levels.
They were the only exam board not to provide formulae sheets, which in many cases for sciences, counts for a good number of marks. A friend of mine went for an interview and was asked to solve a couple of problems, and the interviewer was amazed when he knew how to solve the problems without asking for a particular formula or equation.
The only problem I had with them was at A-Level, when I was taking Computing. WJEC had Teletext in the specification named as a "modern technology"... this was 2009. Teletext hasn't been a modern technology for a decade, but we still had to cover 3 hours' worth of learning on the subject. It was similar through the spec :/