Dixon is way more concise but doesn't provide u with a variety of stats and trends like Riley does. Use Dixon to make notes but still have Riley for other stats and trends etc.
Riley really helps with understanding the fundamentals of economics due to the sheer amount of content - you're forced to understand rather than memorise which can be useful for some students but overwhelming and confusing for others. Personally I found it really good but I know some of my classmates didn't like it at all.
Also as mentioned above Riley has fantastic stats that are generally up to date - I used some in my extended responses + supplemented them with stats from my own research.