I personally would take my time and look at many litters (yes, I know they are ALL adorable and you'll want to take them all home!). Vet your prospective breeder well (as a good breeder will vet you too).
Ask to see Heart and Eye certs for both dam and sire. Make sure that both parents are at least 5 years old (yes I know lots will disagree but this is one thing they were discussing in the prog last night - breeders actually ignoring MVD breeding guidelines). We must not forget that MVD is still as prevalent as it was years ago as well as the SM that lots of us now have to contend with.
See how many generations of the same family the breeder still has or is prepared to put you in touch with their guardians if they retire them. Ask to see copies of both sire and dams pedigrees to check for inbreeding & how far back and last but not least, ask if they scan their breeding stock and if you can see the reports (prob won't make a lot of sense to you but it will usually say whether or not syrinx or malformation present (means affected in some way - maybe not SM if malformation but that is the Chiari malformation).
Make sure that the heart and eye certs come from specialists btw - not just the local vet (I know a retired vet who routinely issues them for his breeder daughter's dogs - he didn't know about SM until i informed him of it 6mths ago - now he thinks he's a leading authority..... - I won't tell you how he euthanised our hamster but I think you get my drift....).
Above all, if you want a healthy puppy then ask on here - people will do their utmost to help you find one.
One last thing. PLEASE whatever you do, don't just go by pedigree. When I was looking for Maxx I rang an extremely prominent breeder whose dogs are quite famous and have won lots at Crufts etc. This breeder's lineage in dogs is in quite a lot of Cavalier pedigrees today.
Anyway, after about five minutes on the phone to this person I was so mortified by what I was hearing I actually just put the phone down mid conversation - nothing more than a posh puppy farmer to my mind
Obviously I can't name names on here but just bear in mind to askloads of questions and if alarm bells go off then heed them :~)
Good luck with your puppy hunt