Synthetic is better, but costs 2-5 times as much. However, you can run extended oil change intervals (10,000 miles isn't a stretch) and recoup the cost that way.
Synthetic flows better in cold weather and is generally superior to regular oil in every way including lubrication and high-temperature stability. Then again, plenty of engines go 200,000 miles or more with plain oil changed every 3000 miles.
Brent