For my two cents worth... we've used Mobil 1 in our race bikes for several years now. Byron Hines originally swore to me that it was the best thing since sliced bread... and I believe in it whole heartedly.
In turbocharged applications, using it eliminated (not reduced) turbo failure, which is normally caused by shutting the engine off at speed, and lack of oiling causing the bearings to scuff.
Piston wear also disappeared greatly... as did transmission wear patterns.
Now... in every engine we've tried it in... we've always seen this pattern... from our 500HP funnybike engine, to a pro stock engine, to stockers... without exception.
About eight years ago... I worked for a major engine builder... and we got involved with Torco as they engineered their synthetic oils. As they did it, they kept having us dyno test their stuff... and we always benchmarked it against a matching Mobil One test.
Clutch slippage, by the way, is not a problem with darn near any oil. Additives, on the other hand, can be.