Used to have hassles with CRC over delivery taking forever, and made the mistake of using next day delivery once which actually means it takes longer for them to ship it, just the next day is the postage they use once shipped.
However price means I still use them and they have got better. Still never next day. Usually allow 3.
I just use whatever really, although I tend to avoid the smaller generic online shops as I can never trust what they say is in stock actually is in stock. A lot of them hold little or no stock and just quote what their distributor tells them, but I’ve been hit a number of times with “oh sorry, it’s actually not in stock and we won’t get them for N weeks/months”. If CRC say it’s in stock, then it pretty much should be as it’s in their warehouse.
For something absolutely next day I’ll pay up and go to an LBS who actually have it in their hands.