Best EU country to ship to? (Least red tape, fewest customs holdups)

I have been shipping product to the EU FBA primarily via Italy, because that was where we first got our VAT number. Now, we’ve expanded and have VAT numbers across most of the major countries, and I’m curious if there’s a better, easier country to ship to. Right now, it seems as if every 2nd or 3rd shipment, our package gets held up in customs because they can’t find the VAT number listed directly on the Commercial Invoice.

So, my question is, has anyone had especially good luck shipping to one or another countries within the EU?