"You're lucky you got out of there."
I read somewhere that both lines were used in different versions of TESB prior to the Special Edition, so if true, I don't know which was used during the original theatrical run. The only way I ever heard it before the Special Edition was "don't taste very good."
This isn't necessarily an argument for original vs. modified; it's just my personal preference. And obviously, my personal preference does not jive with that of Lucas. R2 not tasting very good always worked for me. Never occurred to me that Luke was joking at R2's expense. Never occurred to me that there was anything wrong with it whatsoever, so I don't know why Lucas believed a change was needed. It was an effective line delivered well. "Got out of there" feels flat by comparison. Regardless of which line was originally intended, "don't taste very good" just works better. In my opinion.