Is it worth getting Osmo + now, or should I wait for the next osmo with Zenmuse x4?

The low light performance of the Osmo+ that has been the sore point of most reviews is not that bad if you are using the Osmo+ for personal use. For paying gigs, I would look at the X5 pro models for now. I've heard rumours that the X4 will perform better in low light than the X3.

Wait! Only recommendation I can make :-/

I would suggest you wait unless you need one immediately.