Oh, yeah, very different. Zero character development, and after about the sixth season the plots start to get repetitive. It was very much Jack Lord's show, with everyone (including Danny) playing third fiddle to McGarrett. But it featured some damned gorgeous scenery at a time when Hawaii was still a fairly new state. And nothing beats McGarrett's Mercury Park Lane Brougham.
It cracked me up how during the first season of (new) Five-0,
Steve was constantly ribbing Danny for wearing a tie; rewind to 40 years prior and they're all out chasing crooks in suits and ties.