There are 2 things we are comparing here, each themes free version versus their paid versions.
For the paid versions, OceanWP has a more affordable single site license but is more expensive for multiple sites.
For e-commerce websites, OceanWP and Astra are comparable but will give a slight edge to OceanWP.
As far as demos, Astra is the clear winner with more demo sites.
As for speed, OceanWP will be slower out of the box, but it has speed optimization options to make it just as fast. I like that those options are available.
So it's tough to say which is the better theme, but since both have free versions, I would encourage you to test both out.