Growing best onions possible

Any opinions on growing best onions next year. Is if better to grow from seed or sets? Used to sow seed Xmas time but sets save a lot of time however undecided this year. Facourite varieties? And feeding? High nitrogen early ? It would be interesting to hear how others grow their onions

I only grow sets these days and have been consistently harvesting tennis-ball sized onions for the last few years, since I started using a heat-treated variety called 'Setton'.  I start them in modules (the 24 to a seed tray size) in my unheated greenhouse as soon as I get them and plant out when they have good roots (usually they are about 6-8 inches high by then.)  Clay soil here and the only feed they get is a trowel full of garden compost used when planting.  I only started doing this to prevent blackbirds/squirrels pulling up the sets, but it worked so well I wouldn't do it any other way now.

Thanks bob. Never thought of starting sets indoors. Sounds good