I think the Virgin domestic system is the best of both worlds, they use a mixed crew of AMEs and LAMEs. They both do the turnarounds, if the arriving aircraft for an AME comes in with a defect then he swaps with a LAME.
The LAME fixes the aircraft and departs it, the AME departs the LAMEs original a/c.
This way the aircraft gets a look over by a set of trained eyes, rather than a non-interested bagchucker. And the company gets it savings by having more AMEs doing turnarounds.