I prefer the 3.5 way.
The reduced values of DR are a change for better. I think that the 3.5 values allow to consider a combat against a creature with DR (other than DR x/Magic, which is easy to overcome) in this way: by default, think that the party is NOT going to be able to overcome DR, except perhaps one or two characters, but not necessarily. The creature with a DR 5 or 10 is still possible to fight effectively and IMHO the CR is appropriate when the situation is as such, while the combat becomes obviously easier if more characters have suitable weapons, or harder if you must rely only on spells. When DR is 15 then it is more critical, and cuts off some PCs from being able to give damage at all, especially the ranged combatants.
OTOH, the 3.0 DR had a much more steep threshold, with its higher values, and a less diversity, so that the difference between having or not the right magic weapon was more critical.