We have a Flat Coat and a Lab. I was brought up with Flatties and Labs but have some experience of the other retriever breeds as father trained retrievers for other people.
Flatties are the Peter Pans of the dog world .... they do honestly never grow up. It is for the most part like living with an over-grown puppy for ever. Great characters but can be a handful. In general, as a breed, they love everyone and everything with full on enthusiasm. They have a constantly wagging tail and you can expect family and visitors alike to be kissed to death. They are clever but silly .... clowns ... they have a great sense of humour but don't have one unless you do too! They can be hard work and are always 'on-the-go'. They love family but love everyone and show it. They are not guard dogs in anyway. They adore children but can be a little 'rough' .... too enthusiastic! They are always ready for fun. Alf, even at 9, is straight there if he hears an excited voice or laughter.
I love Flatties but don't think that they would suit everyone. They need lots of exercise and stimulation and can be hyper. Being so people orientated can be a problem if not trained well eg. run to strangers, jump up.
Flatties are not that common but in the last 2-3 years I've had 3 lots of people come and fuss Alf. They had all recently given their Flatties to other people or in one case a rescue because they couldn't 'cope' with their lively behaviour and antics. One lady said it broke her heart because the dog was lovely but just too lively around her young children.
Male Flatties can be very head strong and wilful .... much trickier to train than labs. The female handler presenting the Crufts working gundog display a couple of years ago said, ' You can train 3 labs, to 2 Goldens, to 1 Flat coat. ' I think that is about right.

Labradors are good all rounders. I only have experience of working labs. In general they are easy to train. They are sensible and clever. Working labs usually love their families and children in their family. My picture thing is of our 10 mnth old fox red working lab. She loves our children and is very tolerant and easy going. We find that working labs are sometimes nervous of strangers. Kate is typical of this and does bark at strangers and takes time to feel confident around new people. In general they are quite sensitive and they respond really quickly to training. They don't like to be shouted at and you need to be gentle when training them .... not so wilful as Flatties. Kate at 10 mnths has been on holiday with us and behaved impeccably. Alf at 9 years still needs reminding to behave himself.

Oh, Doganjo is quite right about cancer. There is undoubtedly a problem in the breed but saying that our Flatties have in general out lived our labs. We have had Flatties live very active lives until 13 and 14. Sister however lost one at 13 mnths and I have heard of lots lost in their early years. There is no line that is not affected.
There is not a bad bone in my Flatties body. If you have loads of energy, are very tolerant and have a good sense of humour Flatties are great. If you want an easier life labs are a better choice in my opinion.
Oh, if working at a serious competitive level, then a lab .... no choice. Have a look at Field Trial results ... it answers that question.
Don't know so much about Curlies and Chessies. Have seen them working. It was some years ago. They didn't win much. The ones that I knew of both breeds tended to be a bit on the 'sharp' side ... both with people and dogs. I was told that Chessies didn't always tolerate children so readily as labs, flatties or goldens but no direct experience of keeping these as house dogs.
HTH ...... if you want to know anything about Labs or Flats will try to answer your questions. I

both.
