Yeah, Beast's scholarly personality didn't start to show up until about the 4th issue or so and he became less and less brutish and more civilized as the series went on. He's my favorite X-Men character as well and I've always preferred his original human form (to read about his transformation to the blue and furry Beast, you'll have to read Amazing Adventures #11-17).
Anyways, the original X-men series only lasted 66 issues before being relegated to reprints and ultimately cancelled. It had always been one of Marvel's poorest selling books and you'll see lots of desperate changes in the last 20-30 issues trying to save the series from cancellation.
Despite that, it's still one of the most enjoyable series of that era. Completely ahead of its time and revolutionary and it would take the comic book world decades to catch up.
The "All New, All Different" X-Men (soon to be Uncanny X-Men) took up the reigns in issue #94 and everything you read there will ultimately lead up to the Dark Phoenix Saga, which climaxes in issue #137 and is easily the single greatest story in all of comic book history.
After you read all of this stuff, then you'll see just what a great injustice to the source material the animated series and the movies really were.
Anyways, have fun I know you'll enjoy it.