Well, a tactical reload takes longer to execute from start to finish, as measured from when you decide to start it to when your support hand returns to position, but the really critical time- defined as the amount of time the gun has only one round on board- is comparatively short. It's shorter on an AR than on an AK, assuming equally skilled operators. This is not the end of the world for the AK user, of course, but it is an advantage for the AR.
If something bad happens in mid tac reload, you can always drop what you're doing (literally and figuratively), address the issue with whatever happens to be in the gun at the time (the partially depleted mag or the fresh one), and then gather up what you dropped IF you can. To me, the time the gun spends with no mag inserted is the crucial time. Assuming you're doing a tactical reload (reload with retention), the AR spends less time in that condition.
Mike