From: Southern California
Ok, Mizzlilly, I have to chime in here...
I think which dog you go with should be about the size you want. The maltese are quite small and very trainable, and love attention...a great companion dog. I've had them in my agility class are they are so sweet and easy to train. The Havanese have been in agliity too. They are a larger size with more hair and very loveable and compliant. I did not find them to be so excited about working/learning generally. I've never have worked with a papillion, but know owners of them. The are lively, smart, and very trainable. I've thought of getting a papillion instead of a corgi. But, I like to do sheep herding with my dogs and agility.
So, I'd think about what size dog you'd want, how energetic you want, and type of personality you desire. Each dog has it's own personality and temperment which can be hard to predict. Go to the dog show and talk to the breeders. The breeders are naturally in favor of their breed, but see how friendly the dogs are that you see there and how they behave in the ring...are they jumping around? barking unnessarily, coperative with the handlers? etc.
A short story...when I got my first two corgis, I'd take them to the small dog part of the dog park. The would immediately take over the place and round up and hold all the other dogs against the fence! This did not make the other owners happy, so we stopped going. I knew right then that I had to find some sheep for them!