I'm real regular on UA, usually long INTL and some X-country EWR-LAX or SFO. The new Polaris is a nice improvement and certainly a move in the right direction. The problem with UA (and most probably most legacy US airlines) is inconsistency with service. You can have a great experience one flight and be totally ignored on another. The problem seems to emanate from the lead. The lead FA needs to coral the group to do more than the minimum.
The new bedding is nice, now keep working on improving the catering and get your FA's to do more than serve the meal than disappear.