I'd honestly recommend to expand your orks army at this point of 8th edition.
SM are becoming weaker and weaker everytime a new codex drops. And primaris stuff is repulsive
IMHO
Orks offer tons of possiblities in customization, if you're into that part of the hobby, I'd suggest collecting them only for the chance of having a unique army.
Gamewise they're popular and nicely competitive as an horde with warbosses, weirdboyz, painboyz, big meks with
kff, boyz, stormboyz, kommandos, kannonz and
KMKs.
I prefer using transports or mixing footsloggin mobs with transports and walkers.