With regards to the old aircraft that QAC uses mixture of PA28, PA34s and DA42 apart from the DA 42 yeah they might be old body wise but the maintainance is fantastic. Yeah I heard that their operations is limited to ISA+ 30 as the performance is markedly reduced <300 fpm. ROC.
With regards to DAE I heard they are going under unfortunetly. As I wanted to learn to fly their. Nice equipment they got but a shame. oh well.