Thanks for the new term - "European style" - I hadn't heard that before. DH has an unreasonable hostility towards top sheets so we generally sleep European style too.Duvet w/ four covers. We change them weekly because we sleep European-style (no top sheet).
I've had my IKEA down (maybe 'down alternative') comforter for almost 15 years now, one of the best investments I ever made. Duvet covers are more hit or miss. I find ones with a smooth cotton texture vs a more grabby/snuggly cotton texture work better.