As fatal aircraft accidents go, AF447 was one of the more 'gentle' ones. There was no rock-like surface to break the recorder shells, only other aircraft structure. The pressure is a real concern as is the duration on the bottom.
It is very likely that the fuselage broke around the door opening areas judging from the floating wreckage recovered, thus the area forward of the aft pressure bulkhead probably no longer forms an enclosure.
Similarly, the lower skin aft of the rear pressure bulkhead was likely sheared as a result of hydrodynamic forces and uneven support of the skins in the area plus the removal of the "roof" of the compartment when the VS was torn away and the HS was almost certainly torn away too, so it is likely the recorders made an independent trip to the bottom.
The difficulty in locating the pingers suggests that they were buried in the sea bottom to some extent.
I expect that the recovery team will grab what is left of the tail and check it out only to find it missing its recorders. That is when wreckage distribution theory will come into play.
Once located, the recorders condition determines what will be necessary to get them functional. If they are still dry inside, the probability of data recovery is very high. If flooded, data recovery is still possible, but will probably require the manufacturer's assistance to have a chance of reading data.
I believe that the data resides on an array of static RAM chips of some type but feel free to correct me.