Ever since I found out that I have an allergy to salicylates,I have to be very careful and frugal with onions.I only use small pickling onions and shallots when cooking,while if making a salad I use very thinly sliced Purple onions if any at all.
I can't eat raw onions as I have an intolerance for them but I adore cooked onions! I use different varieties for different recipes.... if I'm using the onions to add flavour and body to soup for example, I would use white onions. For something a bit more robust or for roast onions, then red is best I think. Boiled onions I prefer white. And then shallots or silverskin onions for casseroles and stews.
I love onions and am lucky to be able to eat them without side effects. I use brown ones for cooking and red onions for salads. if they are on special i buy spring onions and will use them raw or cooked. I have planted some spring onions so hope to be using them more often in the future.
I nearly alway cook with the brown onions, but i’ve have had a couple of recipes using a red onion, but i can’t make the recipe until I go out & buy 1 red onion. I used to eat brown & red onions in salads raw, but I don’t like to anymore. My 91 year old mother-in-law has always made a salad of sliced brown onion, sliced tomatoes & a little bit of brown vinegar.