I watched them in chapter order (one a day, I - VI) earlier in the year after I got hold of 1080P versions.
Firstly, after watching on DVD, seeing them in 1080P was like watching them freshly once more.
The prequels are pretty poor, not visually or technically but because they are just so dull and lifeless in terms of character dynamics. And things like R2's rocket boosters and '3PO's head swap and Palpatine melting just make me cringe and weep just thinking about it.
I've seen RoTS three times (once at the cinema, once on DVD, once at 1080P mkv)
I've seen Star Wars countless times, beginning from when I was able to tape it off TV. It's not like the OT is without problems - but what problems do exist are overshadowed by the fucking excellent bits.