InterpartThe German publisher Condor started this series under its Interpart label in 1984. The magazines were published every second month, and the series ran until until 1986 - cancelled after issue #10. So the final issues incorporate the arrival of the Horde, but the Snake Men never appeared. Each issue contained one main feature (covering about two thirds of the pages) and a short backup story.
Obviously, this puts the series in a pre-cartoon continuity (the cartoon was first aired in 1988 in Germany). It shares a lot of motifs with the German audio cassette adventures published be Europa which had started a little earlier and defined the Masters mythos for many young people. The stories put the focus on fantasy, so the magical elements are clearly dominant over the science fiction / technical ones. This often results in relatively drastic and dark storylines. The villains aren't just bumbling idiots, but they all have their own function and character (seriously: what's the difference between, e.g., Trap Jaw and Mer-Man in the cartoon?).
The artwork consistently stayed on a high level. Characters always looked good, they were easily recognizable - close to their toy counterparts, but not slavishly drawn after them. While certain other artists even drew levers used to trigger an action feature, that never happened in this series. Especially the double-page-spreads found at the centre of most issues are very impressive.
Of course, the series isn't without flaws. It has been critisized for not paying much attention on the 'human' element. It's true that there are only very few scenes which deal with character interaction on the royal court, no Teela pining away for He-Man and so on. All this is pushed back in favour of the mystical elements covered in each issue. This is more a question of taste than a real discussion of quality.
What the series really shows is one of the inherent problems of the whole line: it's very hard to write for a character who is, by definition, the most powerful man in the universe. What problem could such a character possibly have which he can't solve easily? That is why the stories in this series often linger on long journeys with many small, but different obstacles while the final confrontation with the story's main villain / danger often falls short: after building up a seemingly enormous threat over many pages, it's often solved by little more than one stroke of the Power Sword.
In spite of these minor drawbacks and some occasional mediocre story, this is probably the best comic series about the Masters ever produced. Sorry to all the non-Germans out there - you'll just have to believe me. In fact, there has been an effort to translate the series into English. Egmont published the stories 'The World Devourer' (from issue #9), 'The Master with Three Faces' (from issue #7) and 'The Siren Song' (from issue #9) in a special issue of their own magazine in the UK in 1987. I don't know if more stories have been published (please enlighten me), but even to call that one issue I own 'rare' would still be a vast understatement. Go look for them - it's worth it!
Finally, a word of caution: Condor / Interpart also published two pocket-sized books which contain lots of extremely short stories (usually just one or two pages). These don't have anything to do with this series, they were done by a completely different team and everything about them is just laughable. Avoid those at all costs!