ubiquitin, You asked what I think, I cannot prove this, yet my answer would be as following.
Most patients, probably no difference in outcome, mainly because the majority of patients are not that sick that outcome is even a factor.
From the very sick patients, Yes some have a better outcome due to the resources of hatzolah.
Again, this is my personal opinion, not sure why you would want my opinion.
For instance, I am familiar with a particular skilled nursing facility that for some reason decided on not calling Hatzolah when they have a sick patient. The nursing staff (completely non jewish) protested and requested that hatzolah be the primary EMS agency for the facility.