Personally I prefer the UNOS (undershoot/overshoot) method i.e. non-timed. Seems to be more accurate and require less fine-tuning after roll-out. The timed method relies on your standard rate turn being spot on during the whole turn whereas monitoring the compass throughout the turn (as in the UNOS method, described above) gives you an instantaneous cue to roll out.
I often combine the two - I use the UNOS method and roll-out. If the heading is slightly off I'll correct with a short timed turn one way or the other.
Each to their own!