I have had 2 Vortech ph for the last 6 (?) years and one of them failed about 2 months ago (worn out magnet). I have also used Koralia 4 ph for the last few years and find they work as well as the Vortech for a lot less money. They do put a little heat into the water and are a little larger but for the money they can't be beat. If I were to start over I would use Koralia 4 ph and save money. But the Vortech is a better ph imho, with a battery backup and a variable speed controller.
Tunze makes very good pumps as well. The controller is very affordable at around $150 at JL for the newer one.