I've got the Hanna Alk and Phos and like them. But I switched to Elos CA. Like it better than the Salifert. Have Salifert Mag right now, but will probably get Elos next time for that too.
You can make your eyes bleed trying to read up on each brand, the problems they've had (or have), or how they vary. While Elos, Salifert, and Hannas all seem to be good enough, none are perfect.