The first time you get a bill for a new engine you will see the benefits of hiring....
I would turn that around by saying that if you are renting, the engine will most likely be sent to the cheapest nastiest engine shop, whereas if it is your own you will use the opportunity to get it done by the most reputable engine shop (probably in the USA), so when you fly you know there won't be too many bolts loose
Buying a plane with a dodgy engine is an opportunity to knock him down by the cost of an engine rebuild. It's the most important bit of the plane (along with the wing bolts).
There is little comparion between hiring and owning. If you own, you get
- total access
- ability to do fly away trips (a huge value to a pilot)
- maintenance done to YOUR standards
- know that nobody else has bent it
etc