As far as I know, sweet onions are just fine for cooking those things you mentioned. They aren't sweet like candy, just a little sweeter than most.

I'll use the sweet onions in cooking, they work just fine. I think the only difference is that they're not as "biting" as a "regular" onion when eaten raw.

Actually the biting onion keeps its flavor in cooking and the sweet oinon looses alot of its flavor. Many cooks swear to this. I was hearing a cook/chemist talk about the chemical reasons for this. It is not imagination, it appears. Also the regular onion keeps longer in storage. But , dang, the sweet onion taste so much better raw.

I plant my onions as transplants in January. Leeks, I plant in fall. Bunching onions are a good. I also grow a chinese onion, or I will be planting them in fall for the first time.

I'll have to buy a sweet onion and try cooking it or using it in salsa to see if I notice a difference then. Oddly, the local box stores don't seem to stock the recommended seed varieties. Perhaps it's too early? Buying onion sets would be a waste since I probably only have room for about 16 of them.

Meanwhile, I came across this thread while cruising through the Allium forum: Short Day Onions. Somebody mentioned a short day red storage onion from U. of Hawaii (Awahia Bulb Onion) that I'm thinking about trying since it's ~180 seeds for $1 plus 50 cents handling charge and 45 cents postage to send order form. As a bonus, they have some edamame in stock.

I have planted supermarket shallots before and they work just fine.

I think I paid $1.something for the onion sets in January. I was able to find a bunch of varieties at the time. I am harvesting them now. Interesting about the Awahia Bulb Onion. Tempting.