Conclusion: With virtually no change aside from the inclusion of two rows of cyclones rather than one, there is very little difference between the DC38 and the DC47 apart from improved sucking performance. It's certainly not the leaps and bounds of an evolution that we saw with the new DC50. That's not to say that it's to be complained about. If you've been thinking about upgrading your cylinder vacuum cleaner, the extra money is worth it, for sucking power alone, over the DC38.
Pros: Small, Powerfull, Easy to use,
Cons: Hose is cumbersome, Dyson DC50 offers more features