Hmm…this is a tough one. T2 was probably the more entertaining of the two, but I still have problems with Edward Furlong being able to tell Arnold to do whatever he says. That part was lame. Therefore, I give it - narrowly - to the original. Both are awesome though. (The rest suck balls.)
T1 is the anthology. Remember waiting for tickets when I was a young kid. In YU everything played with 1-2 Y delay so We had the chance to watch Arnie in the first significant release during mid '80s.
Terminator 2 is better than its predecessor in most technical respects. However, the first movie was original and its producers took a bigger risk in putting it together. Just like for music, architecture, or other forms of art, the value of movies can be derived from their historical significance and influence on the genre, which in this case, created an enduring influence on popular culture. The “best” movie in a series doesn’t have to be the one with the highest standards of production. It can simply be the one that came first.
In addition, for me the best Hollywood movies were in 70s and 80s when FX computerization was not as dominant as today, and the acting was dominated. The Godfather, The Deer Hunter, The Taxi Driver and Apocalypse Now were some of my favorite.
I thought Terminator 2 was more entertaining and was one of my favorite movies from childhood. However, as I grew older I started to appreciate The Terminator more as it was just so far ahead its time and compared to other peer sci-fi movies of that era. I also thought the storyline was more thoughtfully developed there. Both were incredible movies though.
Terminator 2, in many respects (including budget and state-of-the-art CGI that was ahead of its time and still looks great a quarter of a century later) redefined what the modern action/sci-fi blockbuster should look like.
I never even saw T1 until I saw T2, which roped me into the whole Terminator universe, including the books and comics. I am, as many of you know, a massive fan of Arnie, and I would say that this movie was the first one I saw of his to where I was really conscious of who he was. I have since seen every one of his movies multiple, multiple times and what can I say, I just agree with his philosophy on life. And the one-liners are fukking awesome and cast certain tough times in life in a humorous light in a way that millenials will never understand.
So long story short, they are all great (the ones with Arnie, agree with earlier poster about Salvation being utter crap), but T2 is the best.
I remember only for Alien (1), Star Wars (until The Return of Jedi) and Terminator 1 as significant SF movies of that era. Yep, and Predator came after Terminator.