This is my first encounter with Maigret, and do not even think to tell me to go watch some TV series. I have no intention of doing so. The Maigret that Simenon has formed in my head is just fine, thank you.
Police detective novels, eh? What's so special about that? I can think of two things that stand out as special. First, the cases Maigret finds himself with seem to have a personal twist or effect. In the first of three Maigret questions with whether he is really doing his best to find the killer of a reprehensible cretin that he knew from childhood. The second brings Maigret face-to-face with mores of a different era, causing him to wonder how much was lost in the march to decadence. In the third Maigret faces the contrast between a very important case and a case that is only important to him. All this allows Simenon to build Maigret's character as the anchor. The plots are police procedurals, but the stories are about Maigret.
The other virtue is that I have read no one short of the divine P.G. Wodehouse who writes with better economy. Not just in style but in plot. What would be multiple floridly written scenes with all sorts of descriptive trivia in anyone else's hands is a simple and direct exchange of dialogue for Simenon. It's wonderful to read a writer who chooses not to and, more importantly, does not need to waste your time to make his point.
Simenon wrote 76 Maigret novels and 28 short stories and these are my first three. I intend to read more just for the education in omitting needless words.
Should you read the Maigret mysteries? Yes. They are likely a lot better than whatever mystery series you are reading now, full stop. I'm starting another one today.
Late addenda: I started another one as promised (Maigret and the Headless Corpse) and to my shock it is, at first blush, exactly the opposite of the taught, economic prose I just wrote of admiringly. Lots of scene setting and dallying around. We'll see if it's an oddball or not; I hope it sorts itself out. I'm leaving the above evaluation in place for now, as it certainly applies to the specific book I read (A Maigret Trio), but I may have to change my full-on recommendation. They may be hit or miss.