Welcome! I'm sure you will love a calvi- they are lovely, functional and versatile. I have a few ( and some bastia) in both chevre mysore and chamkila, use them everyday and have not really seen any discernable "wear" on them. They are soft to the touch, yet maintain their shape, color saturation, etc. I'm not a fan of epsom or the stiffer leathers, but that's just me- others love them. My barenia ones have patina-ed ( and scratched) but that's barenia and you just gotta go with it or not get involved.
Personally, I vote for chevre, but that's MY vote, not yours. I honestly believe that your biggest problem is that you're going to love it, and then will be looking for another...... and a bastia to match..... and another.......

Good luck with this very pleasant problem ( and oh yes, just to throw another wrench in the works- I am a total neutral lover, but its really nice to sometimes have a bright calvi in your bag- not only looks great, but easy to spot!)