Hi Pako. I don't know much about your climate in Bulgaria, but if it's similar to USDA zone 7b (your profile suggests that?), then I think either one could do OK there. Ischia Green would probably need more protection in the winter than Hardy Chicago (Bensonhurst Purple, Mongibello), but both would need some amount of protection anyway. At least some kind of passive protection, and safer still to do wrapping/wind protection. I have both, and my advice would be to choose based on which one you like the taste of better! Do you like green figs, or dark figs? I like both of these varieties, but if I could only choose one of them to keep I'd probably choose Hardy Chicago (based on my taste preferences). Both are good figs.
Mike central NY state, zone 5a
<edit, about 18 minutes later> P.S. I like both of these figs, and wouldn't want to have to choose just one of the two. But in my climate, I think Hardy Chicago does better (at least so far).