I have a Dr. Cook's bitless bridle that I've been using until my horse sees the dentist next month. It did take a few lessons for her to understand how it works because the pressure is in an different place, but after that we've used it just like a regular bridle. I find that the Dr. Cooks needs to be respected just like a bit; it can be harsh if you really pull on it (and I have stopped my running, spooking green horse with it more than once) but if your hands are gentle it is very mild. I've actually found that it can be more effective at stopping my horse than a bit because when/if you need to really pull hard it's more of an uncomfortable pressure than pain so it doesn't freak her out more in a spook.
There are a few issues with the Dr.Cook that I'm not impressed with, though. It doesn't release pressure immediately when you do so there is a slight lag that makes serious training frustrating. You might look into a side pull to avoid that problem. Also people will give you funny looks and occasionally write you off as a crazy natural horsemanship cook that's afraid to discipline their horse :P
So, if you want something for neck reining that has a good stop if you need it then a Dr. Cooks would probably work well. I find that they are less ideal for schooling with a direct rein.
I am here to learn! :)
Last edited by WalnutPixie; 05-31-2012 at 09:50 AM.