Nowadays, I don't think that talking about the "best" layers or the "best" meat birds is a reality. Historic claims for so many breeds are impressive, but ultimately it's not really about breeds but rather strains. Then, once one gets a hold of a good strain, only time will tell how that strain will fare. Egg production's only as good as any given generation, and if it's not being selected for, it will reduce.
Meat's the same, just different. At least with eggs, they're more or less about quantity, then there's egg size. With meat, there's fast meat, big meat, and good meat. But whatever claims the literature makes, their current veracity is dubious. Again, it's a question of constant selection, and proof is dependent on the strain above and beyond the claims made for the breed.
Then there's a further dilemma. So many breeds are lacking good strains that really resemble the standard, by which I means really represent the Standard. For breeders of these breeds, breeds that aren't possessed of strains that strongly approximate the Standard, there's the added rigor of needing to redirect to the standard.
For a bit of honesty, I don't think it can all be done at once. Through a sort of personal evolution, I've come to think that breeding to the Standard is the most important, at least for my program. By breeding to the Standard of a particular breed, a breeder will bring it closer to the production goal for which it is destined. Then, once a given strain is reproducing reliably, emphasis on production can come into play. I know that the last statement might sound contradictory to ultimate goals. Still if one is beginning with a bunch of underweight birds with horrible feather quality and squirrel tails and then one begins to select for egg-production straight off the bat, one, if selection is done along proper lines, is inevitably going to have to reserve for breeding birds that are far from the Standard. The result will be a strong laying strain of ugly birds, a.k.a. hatchery stock.
I think this is where the change of train of thought comes in. I think that it's not so much what we're going to get, but the question of where we're going to take it. For our path, the only way I've thus far figured out to do it is to be dedicated to a breed or a very small number of breeds over a long period of time.
Thus to anyone asking about which breed to get for this or that, I'd say just do the research into the various breeds and then choose one or two. I think that their past is only a directive; it's their future that is yet to be revealed.
However, what I would say is that it really does pay to get the absolute best stock possible. People seem to undervalue chickens. We buy expensive I-phones and what have you, but if a chick costs more than $5.00, we panic. Considering how much time I've invested into these White Dorking, and how much still remains, and considering how heritage birds are a much more secure long-term investment, I'd gladly pay $20.00/chick for the amount of time spent just getting them to this point.