Always good to try a different line if you are interested in it
I would explore the things you like with other lines then see if Oceania would work for your wants & needs or it could be a "one & done" or even a "no go"
A couple of things on Oceania that are different from Viking that may be a deciding factor for you
they do allow children
They do have a casino
they do not have "free" wine with meals unless you choose the Beverage package with O life choice
No free excursions unless you choose the Excursion option with O Life Choice
Only you will know if the line will suit your needs /wants
Enjoy what ever cruise you choose