They are bright, happy, bouncey, can be VERY barky, shed like CRAZY and are very expensive (time and/or $$) to groom.
I know many, many of these little dogs and they really are very sweet but you do have to be prepared for the work and predisposition towards being fairly loud little creatures. Many people also don't know that they shed as much as they do but MANNNNN, they do drop hair!!
I know this thread is a little old but I figured I'd add a reply as a Coton De Tulear owner myself.
I am extremely allergic to dogs, if I touch most dogs and touch anywhere on my face it gets itchy and my nose starts to run. With our Coton dog (Ollie), I am fine as he does not have fur, he has hair. He is very soft hence the name Coton dog.
dr2little, I have to disagree
Are you sure you have seen pure bread coton dogs? They do not shed, they certainly do not drop hair.
If you run your fingers through their hair it stays, you have to pull hard in order to get some hair in your hand. I would not consider that a shedding dog. The only time he will leave hair behind is when he sits on my center armrest in my truck. It seems to hold on to his hair for some reason, must be the material. Aside form that the only time he will leave hair behind is when you brush him and even then all the hair stays on the brush and when you pull it off you have a very soft Coton ball. lol
He is very playful, always up for fun. Sometimes he will just be sitting on the couch, and he will jump up and attack one of his toys, flopping it around and bring it to you. very random
They are very smart dogs and have a really good memory, They only have to do something once and they remember.
For instance I let him out on the long lead to go pee, he saw a Rabbit in the yard, went running after it and in true dog fashion gave himself whiplash when he reached the end of the "rope". He only did it once and ever since, even if he is chasing an animal in the yard he knows exactly where the end of the lead is and stops before he reaches it. Most dogs will keep running over and over again forgetting what happened the last time.
As for barking I believe that is a reflection of the owner, not the breeds personality. As a dog owner your dog will do what you allow him to get away with. Allow him to bark all the time and he will. This goes for any breed. Ollie will bark when someone comes to the door, I like that he does this. If he continues to bark I tell him to go to bed (his crate) where he is quiet. I have an "alarm dog" that I can simply turn off with a command, best of both worlds IMHO.
If you like them with long hair you do have to brush them often, it doesn't take long and if you start when they are a puppy they don't mind it. My groomer charges $35 for a bath, cut etc. We take him every 4-6 month's.
That is my experience with our Coton De tulear.
Here is a short video of the tricks I taught him, a lot of them he learned at 4 month's.
YouTube - Olie Coton De tulear new tricks sit, stay, sit pretty, up, and more