I think it really depends on the child.
DS (almost 6) loved SB5. He considered the whole test as a fun challenging game (compared to WPPSI-III, which was ok to him).
SB5 goes back and forth, using lots of switching between subject, which helped to keep DS's attention. He is very mathy, visual, geometry type kid. Although he loves vocabulary, and scored high on that as well.
He is not good with timed tests. If you take stop watch out, or even just tell him to try to do it as fast as he can, his brain shuts down and he can not focus.
SB5 was a great match for him, allowing him to score even over the DYS cut off.
