The OHS is of course a great exercise to practice for both weightlifters and CrossFitters. For weightlifter you want to have a strong OHS in the snatch and for some lifters, depending on their relative strengths and weaknesses, doing OHS isolated might be a good idea. The same goes for CrossFitters but for whom the exercise is also to be found in a competition setting whereas weightlifters only do the snatch and C&J in competition.
If you run into OHS in a competition setting akin to Regionals 2013 where you have to find your 3RM max you better know how to get the barbel from the ground to the overhead squat position effectively. The principle we follow here is simple: you want to do the OHS setup and extend the least amount of energy.
Watch the video and begin to practice. Oh, and one more thing (are you reading Dan Bailey?): sometimes it is better to do a medium effort clean rather than a killer heavy power clean. At Regionals 2013 Björgvins strategy was to switch from power clean on 120 to (squat) clean on 125 - it worked like a charm!
Note: Björgvin is jumping a bit too far back in this video. Try to limit the jumping back. A total ban against jumping forward is hereby decreed!