I don't think their is a 'best kit maker' as such Harrison. Many manufacturers make some beautiful kits, and some of these same companies make some that aren't so good. Tamiya, Hasegawa, Italeri,(and Accurate Miniatures, who supply Italeri with some), Academy, even Airfix, turn out some great kits, and are probably among the better known names. However, it's a difficult thing to quantify, as many factors come into play, not least the cost, and overall detail etc. Where some companies charge a high price for a well detailed kit, some others may charge a very, very reasonable price for an exceptionally detailed and accurate kit, but, the same companies might also market some good kits, which are 'average' as far as detaile etc is concerned, but at fairly high prices. Revell are an example, with their incredible JU88, but they also have some on their lists which are good, but perhaps not proportionally such good value.
Whatever the end result, it has to be remembered that it's the designer and tool maker who make the model what it is, and many people forget this when criticising olde kiyts in particular. The moulds for these were made by taking a casting from a hand carved, wooden master, so someone, somewhere, has shown exceptional skill in producing these. Today, most moulds are made by CAD programmes, with the mould itself being procuced by the expensive spark erosion method of precisely cutting the metal which, of course, adds to the retail price.