Synthetic is certainly "better". However, is it "much more better enough to make it worthwhile"? :-)
Case study: my 1991 MR2. Purchased used in '96, with 55k miles on it. Always got fresh "regular" oil (and filter) every 3,000 miles. Roughly $20 per oil change. Was used as daily driver and race car (both track events and dirt/gravel events). The oil pump failed gradually over time (due to being all bound up/clogged with congealed oil). Guessing that the last few thousand miles I drove the car that the oil pump was barely making enough pressure to keep the warning light off (IIRC, it lights at less than 5psi, normal pressure is 60psi). Engine internals were trashed. $4500 engine rebuild was in order at 180k miles (Basically only the block and crank were reusable and BOTH needed machine work).
Now I feed it full synthetic which doesn't have the build up issues. However, my oil changes now cost $70 a pop. Still at 3,000 miles due to the severe service it sees (oil stability is still fine, but lots of dirt/contamination).
So, for a common vehicle it turns into a math problem as to if the extended life makes it worth it or not. In my case, engine parts for this car are getting horrendously hard to find. If I lose another engine I'm probably looking at a $10,000 swap/upgrade to a different engine as there may not be any parts for this one, nor any of the same type to swap in...
