I found the tear down somewhat easier than it's predecessor (IPhone 4) though for those attempting this kind of thing for the first time, extreme care should be taken to ensure the right tool is used for each job (ie. Phillips driver for Phillips screw etc.). I inherited this job from a friend that didn't know the difference between Phillips and pentalobe screws and hence destroyed the head of the first screw (and the pentalobe driver) once inside the unit.

Take care and you will enjoy a new found love for the device that YOU repaired.