As a BB manufacturer, yes. Matrix BB's are good.
As for AEG's, most of the "Matrix" brand guns on Evike are simply re-branded, or just sold under the name "Matrix."
However, the actual M4 AEG's that Evike has manufactured under the Matrix brand name (Matrix Tactical Systems) are good.
Matrix makes everything in the airsoft world and they make everything well.
But I've heard some bad things about their M4's. Primarily the hop-up and its bucking. The poor quality causes BB's to drop out of the barrel when you point the gun downwards, and the battery screws up sometimes. I would go with something else. You can find better M4's for the same price at www.airsoftpost.com