I have tried all three of Shimano's top components and all are equally impressive to me. There have been many, many changes since I have raced so I cannot comment on how they perform in events, but as a recreational cyclist, 105 is fine for me.
I do have one bike that has 1979 vintage Dura Ace equipment on it and this is marginally better than what you could pick up on a Wally World bike. it looks much better though. It makes me wonder though, why all of the top Shimano components of this group were labeled Dura Ace except for the rear derailer which was labeled Crane?
I also really liked the look and feel of the Shimano 600EX group which later became Ultegra. IMHO they performed as well as todays 105 and looked a lot better.