Is it actually good

It’s still good to this day.

It's a masterpiece and one of the greatest films of all time.

isn't the answer completely subjective? depending on the viewer's interests?

Although it is very slow paced, by design to cover what it does, HOW it does, it is a very amazing movie and worth watching once in your life, to see how they rolled in 1968 as far as accurate science fiction worked with no computer graphics. Adding, it is probably best to experience it on the largest screen you can find, rather than a SmartPhone or laptop.

I still really enjoy watching it now and then, when the mood strikes, and the latest HD and 4K versions, we are able to see it better than it ever was being projected in the past.

If you need high paced action, this is the polar opposite.
The definition of an "Odyssey" sums up this film really well:

odyssey - a long and eventful or adventurous journey or experience.

A masterpiece, not only for its time, but for this time as well. A visual tone poem/symphony that conveys its depths through sublime imagery.

You have to watch it to find out. A lot of people love it and a lot of people think it's boring. I love this film (except the last 20 minutes which is beyond me). After you finish, you can read explanations of the ending on line.

I still think to this day it has the best SFX of any film ever made, and that's unqualified even with regard to current CGI.

It's a fantastic technical achievement and the story is interesting. Truth be told it is slow paced and quite long.

It's one of the better films I've seen, but it's not one of my favorites. It's not a film I rewatch often, it just doesn't have that fun factor. In saying that it's a must watch for all serious film fans.

Some of it is interesting, and the effects are good, but it pretentiously labors to be profound and just ends up being obscure and tedious. Worth seeing once, but definitely overrated.

In my subjective opinion, it's vastly overrated. I spent decades hearing sci-fi nerds and film geeks telling me it's a great film, but every time I watch it, and am disappointed.

It's not without merit, of course, there are some fantastically memorable, gripping, and stylish scenes. The dazzling opening, the lonely astronauts on their sterile ship, HAL 9000 becoming an unforgettable character, the final destination of the last astronaut... but the film as a whole is borderline incoheret and deliberately obscures the point of the story. I think some people overrate it because they remember the great scenes and forget what comes in between them, and others overrate it because they think they understand it when others don't, and it makes them feel superior.

And of course some people genuinely love it, and I'm never going to try to talk them out of their love, but the fact is... the film as a whole does NOT work for me. And believe me, I've tried and tried to love it, I just can't.