I have been using synthetic oil since 1978. Full synthetic oil is superior to blended synthetic or standard petroleum based oil for a few reasons. It flows better at low temps, which is very important during cold weather start up when a majority of engine wear occurs. It's molecular structure/shear strength is also superior and it generally has higher temp ratings though truth be told, if you are worried about or experiencing high temps you have problems. Because of it's superior strength, it can be run longer than standard oils but should be monitored with oil testing if doing so. The down side to full synthetic is it's cost. If you do your own labor, you can offset a lot of that cost. Changing oil isn't rocket science and only requires a few special tools. At over 70, I still do my own, in my driveway, regardless of weather.
Here is the problem with changing from petroleum based to synthetic: there is a very good chance, even at just 30,000 miles that your engine contains a fair amount of sludge. Synthetic will cut through and loosen that sludge. Best case scenario, the oil filter does it's job and nothing happens. Worse case scenario the filter gets plugged and stops working or worse, sludge plugs a passage way (unlikely, but possible nonetheless) preventing oil from reaching parts that need to be lubricated.
As stated, I have been using synthetic oil for a long time and am a true believer, having seen first hand how much better it is than its petroleum based counterpart. If the vehicle was mine, I would make the switch, drive for 500 miles and change out the oil filter only and top off the oil lost in doing so. I would then drive another 1,000 miles and repeat the process. Then I would finish out the recommended distance/time interval and do the normal filter/oil change and never go back to petroleum based oil again.