Growth technique dependent factors are compared for molecular beam epitaxy (MBE) and organometallic chemical vapor deposition (OMCVD) that are related to the GaAs on Si epitaxy. The comparison, both for growth processes and as-grown material characteristics, indicates that material qualities of these layers provided by the two growth techniques are comparable in many aspects, but differ in morphological texture, residual stress, and occasionally Schottky barrier height. These issues are discussed further with our recent OMCVD results in order to ensure the OMCVD advantages for GaAs on Si wafer engineering, which are referred as an easy scale-up and a large throughput.