David,
I use Arc Euro all the time for my general cutting materials and bits of tooling, and have never had a bad word to say about their service.
RDG is the other one I mainly use, but sometimes their overnight becomes over two nights. But again the service is exemplary.
Once I find a good supplier, I tend to stick with them. The others are pi**ing against the wind to get into my good books.
BTW David, send me an email with which collets you now have, I may have a few spare collets knocking about, and might be able to fill in a couple of gaps for you.
John