I really hope you're not planning on ordering actual airsoft guns... if you are, no matter who you use, you won't get it.
All 3 will end up costing you about the same otherwise as all will have brokerage and duties fees once it arrives (speaking from experience).
if it's just parts you're after, you can find them at Canadian prices, from Canadian retailers that will be about the same once you factor in shipping, duty, brokerage and taxes.
The Tier One Tactical Operator
Tippmann Arms M4A1
KWA USP .45, KJW P226, KJW hi-cappa