Are you flying economy? If so there are no bulkheads in the bubble for economy. There is an exit row but the bulk heads are in the PE section.
Being the bubble makes no difference to turbulence I am afraid and it is also more confined that the main cabin on the lower deck. If you have young kids who may want to walk about you might be better downstairs.
We have traveled in the bubble many times when DD was small however it was only PE up there then and the aisle used to be extra wide.
Might be nice for the return flight though - as the service will be finished quicker so lights will go off sooner and the fact it is quiet might help your little ones sleep.