i think they are great... the sheer precision of the included dropper etc. made me question my old setup.... as far as price, it is more but - i paid $10 for a cheap calcium test at the LFS 20 tests with foil packets.
salifert Ca test has 100 tests, 200 if you use "low resolution" . The tests are much easier to read and more accurate IMO.
Like Tourkid said, worth a few extra bucks for accuracy. La Motte and some others have REALLY expensive kits. The Salifert kits are a great deal for the piece of mind. I got mine online.