If you are new to growing apple trees, Red Windsor is one of the easiest and most reliable of all apple varieties.
It is self-fertile, so there is no need to worry about pollination partners. It grows naturally in a neat and tidy fashion, and crops heavily. The apples can be picked over several weeks so you don't have to deal with a glut. It seems untroubled by the usual diseases of apples, and the blossom also has some resistance to frost.
Red Windsor is a red sport (natural mutation) of a German variety called Alkmene, derived from Cox's Orange Pippin - hence the good flavour. It has a noticeably redder and less Cox-like appearance than Alkmene, although the characteristic Cox flushed striping can usually be discerned.
Perhaps most important of all, Red Windsor has a good robust apple flavour with some aromatic qualities. It is fairly well balanced, both sweet and sharp, perhaps slightly sharper than Cox.
Red Windsor is grown commercially on a small-scale in the UK, and sometimes marketed as Sweet Lilibet.