I am a firm believer in the benefits of synthetic lubricants. My wife and I put over 140K on a 97 Tahoe that had run Mobil 1 since it was new. Our 04 Tahoe has had it in it since the day we drove it home from the dealer. My 34 will also have Mobil 1 in it as soon as I put a few miles on it.
Amsoil is one of the best, as is Royal Purple.
Anyone who doubts the value of synthetic lubricants is living in the past and refuse to acknowledge the information available to them about synthetics.