If I'm not mistaken the bearings are different on the two machines? The corded version having less vibration. For field work without AC it's an obvious choice, but I have enough Milwaukee red batteries that I'm not keen on keeping everything on chargers, with the addition of festool batteries. Once you attach a vacuum hose an ac-cord is not a big decision. I think it's great festool offers two alternatives
I think if I just needed a quick cut or was doing demo work or on the crawl space of a house or up on a roof I would probably swing for a Milwaukee cordless saw... I already have their batteries so it's not a big financial decision. I also own an old 4" DC powered Makita saw for cutting kerfs, drywall demo, and cutting up junk furniture, in a pinch where accuracy is not a concern.