Hi sir, both phones are good, if you are into games, performance and battery life obviously the oppo wins. vivo v5 plus is running chipset SD 625 while the Oppo is SD 652 you can clearly know what phone is good in performance, since the oppo has a greater chipset than the vivo, thats why the price clearly has its own worth.
vivo v5 plus pros:
higher ppi
lighter than oppo
dual sim ( oppo is hybrid card slot, if u want 2 sim no card slot, if u want sd card u only have 1 sim slot.)
oppo f3 plus pros:
VOOC Flash Charge
higher chipset
bigger display size 6’
has card slot up to 256 GB ( vivo no card slot)
but then its your free will to choose both phones. goodluck