Covenant Eyes is accountability software, not monitoring software, and that distinction is why reviews of it are so polarised.
What it actually does. It monitors activity on a device and sends a report to an accountability partner you choose — typically a spouse, a friend or a pastor. It does not block content by default (there is a filtering option on some plans), it does not hide, and it does not give the partner live access. The point is that someone else will see the report, which works for people motivated by accountability rather than restriction. Pricing is around $17–20/month for one user, higher for families.
Strengths. It runs on iOS, Android, Windows and Mac; the reporting is clear; the accountability model is well suited to couples working on honesty rather than parents policing a child; and because both parties know it is installed, it avoids the trust damage that covert tools cause.
Weaknesses. It is expensive for what it is; the reports are summaries rather than full content, so it will not show you a conversation; installation of the screen-capture component on iOS is fiddly; and if the accountability partner is not genuinely engaged, the reports become noise nobody reads.
Alternatives worth comparing: Accountable2You (cheaper, similar model), Ever Accountable (simpler, mobile-focused), Truple (screenshot-based, more invasive), and plain DNS filtering (CleanBrowsing, NextDNS) if blocking rather than reporting is the goal.
Where it does not fit: if you want to see messages, calls and location on a device, Covenant Eyes is the wrong category. That is a monitoring dashboard — Ultimate Phone Spy covers Android, Windows and Mac with SMS, call logs, location and web history (plans). Used together they are complementary: Covenant Eyes for accountability on the adults' devices, a dashboard for the kids' devices.
One caution from the reviews that matters: do not install accountability software on a partner's device without their agreement. The product only works if it is disclosed, and doing it covertly turns a tool for trust into the thing that ends it.