I've an ID.4 (Since March, 12,000 miles) it's finally "stable" after alot of bugs in the s/w, and was given loan ID.3's on every occasion. My impressions - as Kbfen said and in addition, the ID.4 offers a significantly higher driving position, softer ride & obviously plenty more space, interior trim slightly nicer in the ID.4 with soft plastic (although there is a potential re-fresh to the ID.3 interior looming). The ID.3 offers a more "responsive", "nippier" drive. I've the ID.4 77kw First Edition, stated range is 310miles, I would genuinely say it's more like 270 in good/summer and as low as 240-250 in colder weather.