Wright Tool Wrenches perform as good as SO flank drive and at 1/3rd the cost.
I had a set of the Wright, they were okay wrenches, about the same as my old SK Lectrolite in quality. Perform as good as new Snap-on? I don't know, they took nuts off okay, they were thicker by a bit than my Snap-on, and were a lot harder to clean up. They didn't feel as nice to use. Subjective, but definite differences.
To break it down to the lowest common denominator, they both could be used to take off nuts, so in that sense they performed the same. For ease of use and cleanup and feel to my hands, they didn't perform the same at all. So, it all depends on what you value.
You're right about the price, the 18 piece set brought about $125 on ebay, the Snap on would have brought $400, so about 1/3 the price.
I don't see a huge advantage to Snap-on Wrenches over Proto, SK or Wright in utility. I do see some advantage in usability and feel.
Where I do see a definite advantage to Snap-on is in 1/4" drive sockets, and in hex and torx bits, and in phillips and torx screwdrivers.