I heart the Antigona. I wish I had one. The shape is edgy and chic. And it seems to really hold its shape well. I especially like ones from earlier seasons that had studs along the perimeter or chain detail along the perimeter. There are several videos comparing mini and small on YT. The medium is too big, I think. Seems like Antigonas are not the lightest, but the small weighs 2lb 3oz according to 1 YTer, which is less than my Brahmin Large Duxbury, so I know I could carry it. The mini will be lighter and have the crossbody option, but the opening may be kind of narrow, and I know that kind of thing annoys me. It's not that mini, but for example probably can't fit a water bottle in. I know I get annoyed when a bag is too little to carry my stuff, so I'd prefer the small. The measurements you get for these bags are all over the place because I think people are measuring at different points. I think the mini across the bottom is around 8.5" at the base, but of course is wider if you measure near the top where it flares out. The small you can't crossbody which many would find annoying, but I prefer shoulder and hand carry anyway.
The one thing about the Antigonas is the silly strap connection. For some here, this is an 'affordable' bag, I guess compared to $4k bags? But to me this bag is super expensive (mini is 2k, small 2.4k new) and I can envision myself being highly annoyed at the strap coming off unintentionally on such an expensive bag. I also don't like that it has leather feet rather than metal feet.