i use both. ive just started using grapeseed oil and do really like it as well. but it seems to make my hair a LITTLE fizzier, argan oil helps more with my fizz, though GSO is better for defintion. they both make my hair really shinny and strong and help with growth i use both for my ends, to refresh and to help with "winter hair"

my hair: 3b, high porosity, high density and coarse hair (i think i finally figured that all out)
my hair loves conditioner only styling!
Oils and my own procuts are my hairs best friend
my hair goal length is bra strap length when curly.