I've done it before, but only as a last resort.
I've used all of the 3 big Irish suppliers and some UK suppliers with good results.
However ther was an issue with 1 of the Irish suppliers a while back, I contacted them in a number of ways to no avail.
After posting up here the issue was resolved.
Think what you like of me but as far as I'm concerned fair is fair and I for would like to know if someone is having a problem with a supplier.