I number of months ago I was faced with that exact same choice. Somewhere in the archives is my post on that very question.
I received a lot of good input from Forum members, as I am sure you will.
Since I already had a Jubilee Portuguese and a Pisa Portuguese, here is how I answered that question:

and here is the modification I made, which brought me even greater satisfaction:

If it were my first IWC or Portugueser, I'd probably go for the 5454 due to it being thinner and a bit more comfortable. On the other hand, the 5001 has an 8 day power reserve and is such an efficient winder, once I put mine on my wrist I don't have to touch it at all, other than constantly caressing it with my eyes.
Tough decision. Good luck. Make sure you post pictures once you get it!