In Europe at least the dedicated electronics retailers are clearly cheaper than Amazon, and of course do not commingle. Returns may be a bit more cumbersome, but honestly who returns electronics anyway? Usually you know pretty well what you're getting.

Europe also has laws that require a mandatory "No questions asked" minimum 14 day return period after delivery date. Doesn't mandate free return shipping, but for a € 500 piece of electronics paying a € 4.95 shipping fee in the rare case that you return it isn't so bad.