This. I saw Star Wars Ep IV when it came out. I was blown away by the movie. It had its faults but by and large was a good film and deserved the cult status. Ep V was also enjoyable, Ep VI was okay but the Ewoks ruined it for me as I didn't find them believable. Had they used Chewbaccas people as they originally planned it would have worked for me I suspect.
The prequels were badly acted, badly plotted, filled with unnecessary elements that destroyed the feel of the movies for me and Jar Jar Binks. They also wasted some great actors in those films feeding them really lousy lines. The immediate impression I got was "this was written to sell toys" and it was plotted accordingly.
My annoyance is primarily that the first films were (to me) aimed primarily at adults and I enjoyed them as such. The prequels were aimed at 8 year olds and I try very hard to enjoy them but usually can't. If your introduction to Star Wars was via the prequels, then you probably enjoy the whole set, if it was via Eps IV-VI then you probably don't.