If you are doing a small area its fine. Especially when I want to loosen/cleaning up bare areas for seeding. If you are using to dethatch a 2000 sq ft lawn for the first time, its going be a lot of work.
The tines seem to bend too easily, maybe I had a few areas where it was catching on the lawn. After practice was able to have rake glide thru the grass, taking out a little thatch with very little effort.
Works well when you have it remove a little thatch with multiple passes. Time and patience.
If you use it to take out too much thatch (too aggressively), you expend a lot of energy and force that may pull out clumps of grass along with their roots.