IMO *line* matters a whole lot more than *breed*.
For instance some sources will sell you big good-laying quick-growing peaceful BR's -- others' BRs may be small and scrawny, or poor layers, or real s.o.b.'s to be around.
So I think you need to combine your question WITH the question of where you're ordering from.
If you have a particular hatchery in mind because it is nearby or whatever, then ask for peoples' experiences with particular breeds *from that hatchery*. Or, if you are willing to order from "anywhere", make sure you are asking WHICH mail-order hatchery people got the birds from that they are recommending to you
For instance I could tell you how much I like my speckled sussex, as being quick-growing yummy meat producers AND pretty decent layers AND purty and docile... but quite frankly a whole lot of the speckled sussexes that I have seen of other peoples, or heard them talk about, are significantly smaller and would not give you much meat. So unless you could get yours from the same original source as mine (and you can't, it's a Canadian hatchery), my recommendation would be useless at best and misleading at worst
BTW I second the suggestion to get half a dozen of each of several breeds and see whatcha like.
Good luck, have fun,
Pat