Hi Ianny,
Personally I think it is tough call choosing between the Lange Saxonia AC and the Patek 5146. I have both, in white gold; some wrist shots are below.
The Lange is an exceptionally legible watch in WG which is something I value a lot for certain occasions. The movement is nearly identical to that of the Langematik Perpetual, but the price is considerably less! I personally prefer the design to that of the Perpetual which I find too busy for my taste. That being said, I agree with the critics who feel the AC does not have as unique a design as some of the iconic Langes (the Lange 1, Dato, etc.) and I would not choose the AC if it was to be my only Lange.
The Patek 5146 is a really beautiful piece, with a very different personality from the Lange AC. To me, comparing them is like comparing apples and oranges.
Hope this helps a little,
RLD