Unfortunately my experience with cross-border shipping suggests that delays are associated with cheaper transport, i.e. Ground service.
I have had no delays--none--when using 2 Day Air or, from the Postal Service, Express. (Oh, sometimes the routing showed on the carrier's tracking page seems rather odd, but perhaps better not to ask, as long as the package makes it on time.)
And the absolute easiest, fastest, cheapest method, if you live within reasonable driving distance of the border, is to take the units unsealed through Customs yourself and ship from the other side. Make sure you have the paperwork with you.
I have had no delays--none--when using 2 Day Air or, from the Postal Service, Express. (Oh, sometimes the routing showed on the carrier's tracking page seems rather odd, but perhaps better not to ask, as long as the package makes it on time.)
And the absolute easiest, fastest, cheapest method, if you live within reasonable driving distance of the border, is to take the units unsealed through Customs yourself and ship from the other side. Make sure you have the paperwork with you.