[0] I had been fond of "Albany County Fasteners" but I've soured as they've gradually jacked up the prices while removing free shipping. I don't even like free shipping, but it is a way for ordering to be more convenient as it prevents me from wanting to sit on an order for a while to batch it up.
[1] as opposed to stocking up on an assortment
If I buy a handful of bolts from McMaster or BoltDepot, I'm paying like $10 to ship, on an order this is probably $10 in goods :(
So I'm basically always picking between Amazon and AliExpress.
Time frame it really depends - delivery dates a day or few days out are generally accurate. Most items they stock at a local distribution center, so I get them next day. Some things come from further warehouses of theirs and take a few more days. There are also third party vendor items that are all over the place for delivery time, but you know those by their estimated delivery time being more than a few days out, and saying ground shipping only. (They're slowly taking away "free shipping" from items that require LTL though, heh heh)
For fasteners specifically, their parametric search has gotten better. I'd have Digikey's interface everywhere if I could.