Of these, I prefer [name_f]Sophie[/name_f], but I think [name_f]Sofia[/name_f] is the superior version/variation.
I love both, but [name_f]Sophie[/name_f] gets my vote. She is just so sweet and fun! 
I prefer [name_f]Sophie[/name_f], because I know SOOOOOOO many Sophias (it may not be as popular where you live though, idk!) and [name_f]Sophie[/name_f] just sounds more springy, sweet, carefree, and happy imo! It’s even on my masterlist, though it’s not exactly my normal style.
Sophia’s a bit too frilly for me, but it’s pretty. At this point in my life, I prefer the simple, yet also pretty [name_f]Sophie[/name_f].