I don't have a Carrera but this applies to many watches anyway - straps are easy to change. It is nice to have 2+ options of colors, stitching and styles to swap around. This can totally change the look/character of your watch. You can dress it up, make it more sporty, etc. with a relatively small purchase.
That said, I have a DiModell Rallye (black) and one of Stewart's rally straps (tan) for my Autavia. Both look wonderful. Stewart's was made from the most buttery soft leather - it feels like deerskin. I am sure the others' straps are equally nice.
I now realize I need to buy another strap or three for mine now that I have written this.

: Wow .. thanks for all the feedback .. I thought the hard part in
: this journey was buying the watch .. sounds like almost equal
: energy is put into finding the right strap ..