Sorry for the use of the term batteries instead of cells, English ist not my native language and in colloquial German, the term Batterie is (incorrectly) being used for single cells as well.
About the recommended charging current:
C/5 might be the theoretically best current, but I have seen quite a few chargers who miss the -deltaV drop at these currents because it is too smooth, thereby overcharging cells.
Overcharging is a lot more damaging to NiMH cells than any good ultra quick charger on the market wold ever be. Only a deep discharge (possibly even followed by a reverse of polarity) is worse.
Also, most people, including myself do not charge cells often enough to really worry about reaching the maximum cycle number. If you recharge your cells 4 times a week, 1500 cycles would mean a 7 year service life.
Most people will recharge their cells a lot less often, thereby reaching a multitude of that so I just don't see the point.
Given that even Sanyo's data sheets state a 1C charge, I still believe a 1/2C or 1/3C charge can be done without worrying.
PS: NiMH cells and Li-Ion cells/batteries like the LP-E6 cannot be compared. Their totally different chemistry leads to fundamental differences in the charging process.