Fast and unstable does not sound good. We recently had issues with the windows install crashing due to WBEM copy errors. That crashing means that during unattended install the installer cannot do/find something, drops the ball (stops copying, registring etc) and moves on to the next step. This has all been fixed in nLite 1.4.8. The crash would generally leave some errors in setuperr.log though. The installation loitering at t13 is normal, see previous posts, and it is a matter of taste whether long is too long. I would be more concerned about the installation being too fast there.