I've got the Aquamaxx T3i with a PH Probe, Custom Dual Stage Regulator, 20 lb tank, and lots of Reborn and Remag and now the Kamoer Peristaltic Pump to control the water through the reactor. Some tubing, silicone and rodi. I lost count on how much. Maybe $1,500 total.
The Vertex are also nice, or a smaller Geo. I think in the end they are just holding chambers for media, the more important part is getting a quality regulator. Some people don't like thumb screws, so there are reactors that have threaded lids you can unscrew rather than unscrew multiple thumb screws. I saw an automatic calcium reactor from Aquarium Engineering but they are really expensive.