Max of Oasis Plumbing is great.
(1) His price is competitive yet he does not cut the corner to do the job.
(2) He shows up as promised. He cleans up after he finishes the work.
(3) The water after the new water softener is cleaner, less deposit. I usually need to clean the kettle with vinegar every 3/4 days. Now it has been more than a week, there is almost no deposit.