lmer and method call

Douglas Bates <bates <at> stat.wisc.edu> writes:

(lmer)

The default is PQL, to refine the
starting estimates, followed by optimization of the Laplace
approximation.  In some cases it is an advantage to suppress the PQL
iterations which can be done with one of the settings for the control
argument.

I had found out the hard way that it is often better to let PQL 
play the game rather loosely.  Yet I never dared to tell someone, for fear
the approximation could end up in the wrong slot,

Any rules (beside trying variants) if I can trust such a result?

Dieter