My answer to the first is " Does it matter?"
.You can now buy a digital SLR complete with a 'kit' lens and 12 million pixels for well under £400. Used with intelligence and care and shooting RAW files it should be easily capable of producing a 24"x20" print and let's be honest, that's plenty big enough for most everyday uses.
From the same manufacturer you will also have the option of spending perhaps £5,000 or more for which you will get a much sturdier construction, a faster, higher spec lens and maybe double the number of pixels. You will be able to produce bigger prints with a smoother tonal gradation and also bounce your camera off the odd wall without doing too much damage
The question you must ask yourself is, " Do all these advantages justify spending six times the money?". If you only print up to A4 or occasionally A3, the answer is probably no. If you regularly produce bigger prints and use the camera as a day to day tool from which you earn your living then perhaps it's a yes.
The BIG question though is " If I love this beautiful photograph in front of me and it moves me to tears every time I see it, does it matter what sort of camera was used ? "
A camera is just a tool and no more and if it does the job required of it then the make, model, prestige and cost are irrelevant.
As my old tutor Prof John Hannavy once said to me, an observation that has always been a touchstone for my view of photography, " A camera is just a dark box with a lens on the front, it's YOU that takes the photograph "
Which camera is the best one, THE ONE IN YOUR HEAD.