By far, the most successful Frankenstein of the comics was Prize Publications' version, created by Dick Briefer! Sometimes he was portrayed as a serious monster, and sometimes he was played for laughs (not at the same time, mind you!). I think it started out seriously, and then went to humor, and then back to horror again.
The best coverage of Dick Briefer's Frankenstein was a chapter in "The Great Comic-Book Book," which you can order below:
I'll be featuring more of this version of Frankenstein here and there in the future!