I have a 400 taillight, I ran it on the medium steady mode since I felt that the 400 was far too bright in high mode for rear approaching urban motorists, plus it extends the run time of the battery.
My only dislike for the DiNotte is the cost, I never was comfortable in having a complete lighting system being the same or more than the original purchase price of one of my commuter bikes, and having to replace the lighting system in case of theft.