Which brands work well? We are currently trying to decide on which one to purchase.
We have the Dogtra 1800 NC. You can find less expensive models but we ponied up for the 1800 because it's waterproof (and our dogs are always swimming), it has both "nick" and "continuous" zap buttons and it had a good warranty. It also has 1-10 settings for shock strength.
But, I'll admit that it worked so fast that we probably could have gone without all of the bells and whistles.
I know a local store limits the returns on these collars to 1-2 days because people were buying 'em, training their dogs, and returning the collars a week later.
Good luck