Paul Padilla comes to my house every six or so months to service my RO system. I consider him a member of a dying breed - a repair person who takes pride in his work.
When Paul comes over he's pleasant and charming. He's very tidy, emptying out the under-sink contents and making quick work of changing the filters and assuring that all parts are in good working order. He always shows me the filter (the worst part of the experience because it's always disgusting), cleans up after himself and takes all his trash with him. The only evidence he leaves is better tasting water.
In contrast, other repair people I've had in the house have damaged floor tile, left their trash or other messes (one person actually left pounds of sawdust everywhere), they're rude, dismissive and often do a half-ass job. These people are at the opposite pole from my RO guy, Paul.
Paul does a terrific job, he's reasonable and he gets to you within a day or two. Use his service, you'll be glad you did.