All airlines have issues with tech aircraft, just luck of the draw if you keep getting stuck with one, flown 12 flights with flybe never been late, but have had issues with EZY before, where as someone else might of had issues with Flybe but EZY might be on time every time.
End of the day getting delayed by tech aircraft might be a big inconvenience, but I'd rather that than having my safety and everyone else's compromised!