I don't know, I think if somebody had never seen the ot before and started with the prequels, the turn in episode III might have been pretty shocking. Really, whichever way you watch first you will see stuff revealed that will give away what happens in the other 3.

If someone asked me which to watch first. I'd say oot, then prequels, then Special editions if he/she is still interested. That way you can see it both as audiences did and as the chronological saga.

I still think episode one looks the best on dvd. It was shot on film unlike II and III and the colors are not totally botched like IV-VI. And is presented in anamorphic widescreen without DVNR smearing. I now know what edge enhancement is, I've even seen screenshot examples from the dvd but I've never noticed it on normal tv playback.

(Laputa) Castle in the Sky region 1, now that is an example of bad edge enhancement. I think it looks worse than the oot dvd's. And by the way, Colonel Muska in the (1998 Disney) English dub is voiced by Mark Hamill.