Even with the effects I notice now, I can't say it bothered me when I first saw it, nor does it now. Maybe part of it was that at the time, that was the state of the art effects, and the standard. You couldn't find "better". So I never really looked for the flaws. Today, maybe people notice issues because our expectations have gone up, and if someone who never saw the OT, but watched the prequels or some other modern sci-fi, or maybe even something a bit older like T2, then saw the OT, might notice the effects issues more than someone who grew up watching Star Wars first.
I think its somewhat silly to be put off by the special effects stuff. I'm also a fan of old 40's and 50's sci-fi such as Flash Gordon, Buck Rogers, etc, and that stuff looks terrible by modern standards. You can see the wires holding up the ships, etc. But it didn't bother people of the day, because these things were very popular, and are still enjoyed by many. Basically, I think that the noticability of special effects stuff is somewhat determined by what you grew up with.
EDIT: I just thought of something else: I think that it also depends on how much you look for mistakes. Some people just have to find mistakes, and aren't happy until they do. Others can gloss over them.