Bond was ruthlessly effective in this...
Gosh, I actually love this movie.
I never liked Roger Moore as 007. Yes, he was quite charming and well spoken; his elocution is just about pitch perfect. But he always seemed more playboy than professional, and it was hard to see him as an effective 00-agent in the role... until this film.
Bond seemed focused and resolute on what he was trying to achieve, and I loved how he finally channeled the strict and professional agent he should have been to retrieve information and deal with the baddies. Connery always seemed as if he was playing Bond as if Bond meant business, but Moore always felt like he was being lazy and just putting on a show.
Even though the runtime was about the same as other Bond films, the intrigue of Scaramanga's and the cat-and-mouse centered around control (or suppression) of solar energy was quite the twist. The film also never really slowed down and I thought they made good use of some of the set pieces, chase sequences and action beats.
I've always caught bits and pieces of this Bond film over the years but never really gave it a full look-see, mostly because of my distaste for Moore, or rather my distaste for his performance as Bond (he's still a fine actor otherwise).
It's a shame Moore didn't channel the angst and driven ruthlessness he displayed in The Man With The Golden Gun in other Bond films, as it could have made them far more enjoyable than what they were.