Since you studied both, do you mind to share with us your oppinions about the similarities and differences of those two styles?
First, I am not a Sensei - I am just another guy doing aiki that is willing to share what I know with others of a like mind
Second, I am not sure what you mean between styles. Tohei's model is a style of Aikido that teaches ki development and technical waza. What Dan is teaching is not a style nor is there any waza taught. All he is doing is teaching body conditioning for the development of internal strength via solo exercises and paired drills. The use of ki/qi/intent is important for the success of the exercises, but Dan does not really teach its development - he will give pointers on how to do it, but it is not his main focus.
However, this is where Tohei's ki development can compliment what Dan is doing. The application of Tohei's four principles of mind and body coordination is an excellent start for learning internal skills - internal strength just can not happen without a coordinated mind and body. However, it is just the crucial first step in the development of internal skills - Tohei never took his model to the next step, but Dan has.
I hope I answered your question to some degree.