Every runner is different. Stand at the finish line of any race and you can see that. Good form, bad form -- if it gets you across the finish line, it's hard to argue with. But if you're interested in shaving minutes off your time or reducing the number of injuries you have to deal with, altering your form may be the best place to start.
Changing running styles is not something to be taken lightly. Over the long run, better form may prevent injuries, but too many changes too fast can also do more harm than good. The best bet is to start slow. Take an inventory of your running motion and see if you can identify room for improvement. Try videotaping yourself or visiting your local running specialty store and asking someone to take a look at your form. Is your stride too long or too short? Do you land on your heel or swing your arms too much?
Once you have identified the area you want to work on, incorporate it slowly into your normal routine. As you become more comfortable with a new movement or technique, extend the amount of time you focus on it until it becomes natural. Once that issue is resolved, move on to the next. This can be applied to both pose and ChiRunning styles, and proponents of each recommend taking a long-term view of adopting either one. For most runners, it's a lifelong activity, so there's no need to rush a change that might derail you with an injury. After all, slow and steady wins the race.