Honestly, how often does the average reefer need to test anything (excluding temperature)?
If your tank is "stable", is testing daily a necessity?
If your tank is not "stable", then test more frequently. Possibly daily, but is testing multiple times a day a necessity?
From a price comparison stand point, no automated tester from any manufacturer will ever make sense over manual tests.
For me, an automated tester would add convenience. The Maven would also add redundancy to my current controller.
Would it make financial sense, no way.