Claymore was the 1st of its kind that I read (monster manga). I got to read Berserk way later, but I think I still prefer Claymore.
First of all, Claymore's world is not very vast. It's set on an island, and it remain so throughout the story. This makes it's environment stable. The story telling was also swift. First we were introduced to the monsters (youma), then the warriors (claymores), then to awakened being, then we were introduced to the strongest 3, the abysal ones. From one chapter to another, there's more and more mysteries revealed, which has kept me going. The fights are good, claymores and youma / awakened fights are always enjoyable to watch. The author did well to keep the power balance, the monsters are naturally stronger, but the warriors fight smart. The characters are well drawn and depicted. Deaths come one after another, but it wasn't all that grave, there are times to mourn but the story goes on. Gore scenes are part of some fights, but Claymore is way less gory than Berserk.
I actually like how it ends. The anime end with a more standard power-up style victory, but the manga ends way better (at least for me). There's some possibilities for sequel, involving larger world related to Claymore's, but Claymore as it is has good end and where it end it become good story. So if you don't mind about some gory scene, and interested in human vs monster themed story, Claymore will be a good read.