M4 is the perfect steel for a small fixed blade in my opinion. They really dropped the ball on this one. S30V is one of my least favorite steels because every one I've owned has chipped under mild use. I will not be buying this.
I've never owned a knife with an M4 blade as I prefer stainless and like M390 as my high-end steel. Have you had any Benchmades with S30V chip? Were they older or newer models? My understanding is that the heat treatment is key to S30V's strength versus brittleness and was told Benchmade has made great strides in their current heat treatment process. I read somewhere that early production Benchmade S30V blades did have some brittleness, but it is no longer an issue. I hope it's true because I own the Benchmade 183, 162, and several Ritter models that use S30V and haven't had any of them chip yet.