Finland is replacing, at a cost of over $700 million, its three year old Russian SA-11/17 (9K37 Buk) anti-aircraft missile systems, with Norwegian NASAMS. Norway developed this system in the early 1990s and deployed the first missiles and radars in 1995. NASAMS uses the American AMRAMM radar guided air-to-air missiles fired from a six missile container. This ground based AMRAAM weighs 350 pounds and has a range of 30 kilometers (it's radar can see out 50-70 kilometers), and can hit targets as high as 65,000 feet.
What makes the AMRAMM so effective as a SAM is the capabilities of its guidance system (which is about two thirds of the $400,000 missiles cost.) Testing also revealed that AMRAAM could be used to shoot down cruise missiles.
The Russian SA-11 uses a 1,500 pound missile with a range of 30 kilometers. Even with upgrades, the accuracy and reliability of the AMRAAM is superior to the Russian missile. Four of the SA-11 missiles are mounted on a tracked transporter. The AMRAAMs are protected inside their canister, which means fewer maintenance problems. The SA-11 is combat proven, having recently been used in Georgia, by both sides to shoot down aircraft and UAVs. But the Finns believe the AMRAAM (also combat proven) bases NASAMS is a better long term choice. There's also the suspicion that Russia may know things about defeating the SA-11 that they are not sharing with the Finns.
Norway pioneered the use of AMRAAM as a surface to air missile. The Finns received the SA-11s in payment for the $300 million debt that would have taken much longer to get paid off in cash. Russia has paid off many of its older (often Soviet era) debts with modern military equipment. Some of the recipients have found that the stuff wasn't modern, or effective, enough.