Factory Sealant is quicker to use, can be used wipe on and wipe off a panel at a time if you like rather than the whole car, allowed to cure then removed with the EGP.
For me the EGP looks better, both the CG M-seal and Factory Sealant look washed out and grey, rather than rich and deep on black in bright sunlight. The EGP blows away the Chemical Guys Factory Sealant away in durability terms, 3 or 4 months plus for the EGP, a month max if your lucky with the CG's.