Mike_C did a review of both of these a while back in this thread:
Personally I have tried them both and ended up buying Ormonde Men. Isfahan has however grown on me and I may be purchasing that next month. I can't sum it up any better than Mike_C - his review is on the spot. I definately see a similirity between Isfahan and L'Artisan Navegar but I think Isfahan is better. I guess if they were to make a Piper Nigrum Fresh it would be something like Isfahan. You may be able to ask them for samples of both. Failing that I have samples of both that you can have - if you're interested just PM me.