The most surprising part of the beat in process to me is just how bizarrely resistant some discs are to it.
Case in point - I had this X buzzz that I decided to experiment on, as I really liked the idea of bagging an US buzzz.
Blasted that thing into a brick wall to the point where I ended up with a small cut from one of the gashes ripping away from my hand. Bended it like crazy, even resorting to boiling it and letting it cool in a little "jig" to produce a permanent deformation. The damn thing went from 5/4/0/1.5 to like, 5/5/-.5/1 or something. Could not get it to turn over or stay right reliably.
On the other hand I have had some success in beating in discs, mostly drivers. Also, putters seem to beat in nicely/somewhat quickly as well. Mids I guess are in a bit of a no man's land where they have that beefy rim, but they aren't deep enough for impacts to have a lot of leverage to bend the rim.