I can't speak to the effectiveness of the Redington rod, but I will say that the length of the rod you purchase will depend on what type and what size of water you'll be fishing. If it's spring creeks or canopied streams, then the shorter rod would be preferable. But if you'll be fishing big (read wide) rivers, then there is really nothing wrong with a 9' rod. It will help with mending line over the currents, and can be particularly useful highsticking nymphs.
Hopefully someone else will chime in with a review of the rod you've asked about here. But in the meantime, think about how what type of water you'll be fishing will determine what rod length is best for you.