Registered.
I don't think a purchaser should be charged a premium to have a pedigree puppy registered. Just seems like a way to get a bit more money from the purchaser to me.
In England the breeder usually registers the litter anyway and the new owner can have the individual pup's registration done (or the breeder can do it for you) - just requires the registration fee to be paid when the pup goes to its new owner and ownership is transferred.
My understanding is that if the breeder does not register the puppy him/herself for the purchaser when transfer of ownership is made, the option should be there for the new owner to register it if they wish and they are given the transfer application paperwork/details by the breeder.
If there is a valid reason why the puppy should not be registered, the reason/s why must be made clear to the purchaser and it should be part of the purchase agreement.

I want a mini bull terrier bitch to show and maybe breed so would have to be KC registered

I don't care provided I am happy with the breeder.

My two larger dogs are KC registered, my Yorkie is not.

Personally I think other factors (such as breeding ethics) are more important... but if I had the choice of two breeders and both fulfilled all other criteria equally and one litter was registered and one was not.. and I could only go view one litter, I would probably go with registered.

Obviously that is a little contrived, as you would probably visit or speak to a number of breeders and get a feel for them in the process - and decide which to visit after getting to know them a little.

If I was to buy a pup it would be a working sheepdog

And I would know the farmer, the pups parents, aunts, grandparents and other siblings

To me the paperwork is unimportant as I wouldn't be breeding or showing the pup

TBH, if it were being advertised as from pedigree parents and were not to be registered I'd really wonder why? Perhaps being bred from dogs that have endorsements on their pedigree papers?

Anyhoo, my preference if I were to buy a pedigree dog would be for it to be KC registered.

I wouldn't touch a 'pedigree' that wasn't KC reg.

Only the breeder can register a puppy (or indeed the whole litter) All a new owner can do is transfer the registration into their own name. It is not expensive to register a litter so if a breeder were to say they don't register due to the cost alarm bells would be ringing for me. I would never buy an un registered pup.

i'd prefer mine to be registered but thats because of what i like to do with them.

however when i had my pups, i didnt register 1 puppy in the litter. thats because he was going to my dad, i knew my dad didnt want anything other than a pet, wasnt interested in history pedigrees etc, so i didnt bother spending the extra £14 odd i needed to.

The dog I nearly got the farmer didnt register her or the litter - he would have done at an extra cost - but as that involved him having to drive into town (30 min drive) I saw no warning bells at all - its just paperwork