I've never used one (don't have anybody to teach me), but I think they are appropriate for a certain percentage of dogs in limited situations. Crittering, for example, and reliability off-leash in a dog who already understands a recall.
Interestingly, for those who use spray bark collars, there was a woman with a dog at our obedience class on Saturday whose other dog takes the class prior to ours. She was put away, but she's a barker, and the woman was using a remote collar with unscented spray. I have a hard time accepting the use of citronella as dog noses are *so* sensitive and the citronella takes awhile to fade away, which means the dog is still being corrected long after they've quieted. Unscented spray seemed like an interesting option.
Interestingly, for those who use spray bark collars, there was a woman with a dog at our obedience class on Saturday whose other dog takes the class prior to ours. She was put away, but she's a barker, and the woman was using a remote collar with unscented spray. I have a hard time accepting the use of citronella as dog noses are *so* sensitive and the citronella takes awhile to fade away, which means the dog is still being corrected long after they've quieted. Unscented spray seemed like an interesting option.