What is the difference between conventional oil versus synthetic oil?

I know that synthetic is man made and it will last longer between oil changes. But i wanna know the details between using each and how it varys on low milage cars and high milage cars? What are the pros and cons of using synthetic compared to conventional? And should i switch to synthetic for my 96 toyota 4runner 4 cly with 200,000 miles??? I also heard that if u start using synthetic you shouldnt switch back to conventional because it will cause some kind of damage to pistons or piston rings? HELLPPP!!!What is the difference between conventional oil versus synthetic oil?
listen to what my husband says,he owns a repair shop, good luck,hopes this helps and don,t forget to change your air and fuel filters too.What is the difference between conventional oil versus synthetic oil?
first off i,ll start with the last part of it,you can switch it back anytime you want to there's nothing in the oil that prevents you from being able to switch back ,secondly ,synthetic oil holds up better because it has additives in it that resist breaking down under harsh driving conditions,which makes it last a lot longer,there are no cons to using synthetic oil,and it was designed for higher mileage vehicles,so yours is just right to use it in,and any time you want to switch it back you can,i don't know who told you it would do damage but they was wrong,all synthetic oil is,its a better grade of oil for any vehicle high or low mileage,using synthetic oil will probably be the best thing you can do for your vehicle,good luck on it, hope this helps.
synthetic oil is better because it is suppose to give you better engine protection,gas mileage,longer intervals between oil changes,no more dry engine startup con is it costs 5 to 7 dollars a quart it will also stop engine smoke on worn engines it will not burn like conventional oil will. be sure to use right wieght oil in your vehicle can change back anytime it will not damage your engine at all i would switch asap,
It is not worth the cost believe me ,you keep your oil changed it will run fine.
some people say synthetics will cause rubber seals (like rear main, cam, crank, etc.) to harden resulting in leaks... i used sythetic for a while but switched back to regular. no problems.