Do the effects still hold up?

All special effects will become dated with time, including the acclaimed ones of today. So to me, the real question to ask is whether the filmmakers did the best they could with what was available at the time. Do the effects work for the story?

Also, while more modern special effects may be technically superior, they're not always better,. Peter Jackson's CGI King Kong was simply a big "realistic" ape. Willis O'Brien's stop-motion King Kong is a distinct personality, and all the more so for being "unreal" which actually makes him more convincing). The effects on the original Twilight Zone are minimal at best, but those stories still hold up today.

And as previous posters have noted, Logan's Run isn't really an effects movie, it's an ideas movie. The effects support the story well enough, but they're not the focus. For me, the movie still works just fine in its essentials. And some scenes still have a real impact, such as the ruins of Washington, or the flashy creepiness of Carousel.

Besides, what CGI effect is going to be better than a barely clothed Jenny Agutter? :)

i liked some of the models

Not really. When Star Wars came out a year later and revolutionized special effects, I think this movie already looked dated. That was 1977 I believe.

Love the movie and story but no, it’s pretty dated SFX wise.

The movie is good, the effects are not.

Hollywood hasn’t come up with anything in the intervening years to improve upon Jenny in and out of that slip of that satiny green dress of hers. Thankfully, women don’t wear bras in 2274.

fx not bad , miniature cityscapes are the worst bit

They didn't even hold up then. When I saw it for the first time in the late 80s, early 90s, it looked a bit rough.

Star Wars came along and ruined everything. It set the bar so high everything else was compared to it.