Not to direct people to other sites, but go to the forums at bobistheoilguy.com for everything you ever needed to know about lubricants, filters, coolant, and a ton of other automotive maintenance stuff. There's a section on there for competition lubricants too for you racers.
To briefly answer the question, basically yes, they're right. Some (actually most big name retail "synthetics") are severly hydrocracked petroleum basestocks (known in the industry as Group III). Castrol Syntec, Valvoline Synthetic, and a bunch of others fall into this category. Others are PAO-based Group IV. Note that most of these are still derived from fossil sources- natural gas is a big one. Mobil 1 has traditionally been known as the standard bearer of this group, though that's in question now. Amsoil is another big name PAO. The most extreme synthetics right now are ester-based Group V, of which Redline contains a large proportion. Now whether Group IV or V is actually "better" than Group III is a matter of much debate. Again, if you're interested in this at all, I highly reccomend BITOG.
And one other thing- there is a TON of bad information out there about oil. Everyone hears these old myths from their buddy, their mechanic, a parts jockey, some truck driver, whoever- most of it is total garbage. Unless they have hard, scientific evidence to back up what they're saying, be very suspicious. Just because it's "common knowledge" doesn't make it right.
