calliecritturs:
Honestly, if the breeder has puppies NOW with absolutely no wait? That's not a good sign. If the breeder is perfectly willing, no questions asked, to sell you a puppy -- NOT a good sign.
Why is that?
There are multiple ways to check out breeders. In a rare breed such as Entlebuchers, most breeders will likely all know each other or at least know of each other. You can ask for references from other breeders and/or puppy owners. With rare breeds, you often won't find a breeder close by but a plus is you will find a lot more dedicated breeders who "do stuff" with their dogs, are knowledge about the breed and health issues than you will find casual breeders. All breeds have parents clubs, so you can check the parent club's website to see if the breeder is a member and a part of their Code of Ethics Program (membership doesn't make or break a breeder though, it is just a resource). I would also suggest joining a breed-specific email list, which is a great place to learn about the breed and breeders. You can often ask on such a list about specifc breeders as long as you ask for replies to be sent privately. You can probably contact the breed club to ask about breed specific email lists as well. They also have a list of upcoming shows, which would be another good resource for talking to breeders. The breed club in this case is: http://www.nemda.org/
As everyone said, expect to be questioned about your lifestyle as it would pertain to the dog. And to be educated about the breed and their specific needs. I agree that if the breeder is only 3 hours away, you should consider visiting them at home. Having puppies available now or soon or not for awhile or having/not having a waiting list says absolutely nothing about if a breeder is good or bad. What the NEMDA says is important for breeders is maintaining genetic diversity, breeding physically/mentally stable dogs, breeding dogs free of heritable defects such as mon-orchidism or crypt-orchidism, ectopic ureters/ hydronephrosis, hip or elbow dysplasia, heart defects, for health the importance of OFA and/or Pennhip is stressed, along with yearly CERFs and an OptoGen test (DNA test) for an eye condition, breed dogs no earlier than 18 months, have no more than 6 litters out of one female, lifetime responsibility to puppies, screening homes, keeping accurate records and DNA IDing all breeding stock. You can read their detailed requirements for breeders to be listed with them on the website I posted above.