Howdy,
I would have to comment, that what you are seeing is the result of longstanding marketing policy. Stihl enjoys a captive market at consistant volume, and they can sell every foot they make. The chain has gradually improved over the last several years to the position that it is now better than competitive and acceptable to most professionals, with the exception of a few of the top end bushler's (Those paid by what they cut).
Oregon on the otherhand has faced a drastically declining world market, now approaching half the volume it used to be. This added to the loss of the Stihl buisness, means the company has dramatically lost chain buisness. The policy was to keep competitors out by maintaining a price so low that a competitor could not get started, or manufacture to a competitive level. Stihl simply defeated the policy, by starting up on a ???? the cost basis, and with a goal of producing a better chain. This was coupled with a masterful wordsmithing department marketing through their own distribution and dealers.
Oregon has in fact made Stihl's position rather unassailable by lowering the general quality of the chain slightly in the process of lowering their costs. They have the additional disadvantage of having to be a cash cow for their owner, Blount.
The quality level difference is very slight, but does now exist. For most people, the Oregon chain will easily do a satisfactory job. The performance level of RS vs. RG seems very competitive if both are correctly maintained. Oregon may have a slight edge as filed and Stihl may have a slight edge out-of-box. The Stihl has far less initial stretch (about half) and equal thereafter.
One would have to say the best value would appear to be Oregon, for most people. That's my opinion anyway.
Regards,
Walt Galer