Positives:
- Idiot-proof, works out the box
- Novice and expert mode
- Listens and responds to community
- Beautifully designed interface
- Massive blocking list.

Negatives:
- First install: 'Analytics and "Human Web Data"' is actually opt out which is predatory for new users.
- Smart filter allows certain ads and tracking sites (Google ads for example).
- Owned by Cliqz GmbH who profit off anonymized data collection. They have to play nice with competing advertisers and trackers.
- Proprietary closed source/ partially open source.

I suggest using these addons who have no ties to user data collection/advertising as of now:

Ublock: Blocks ads / trackers
Umatrix: Allow/deny third party elements
Cookie Auto Delete: Keep useful cookies, auto delete trash cookies.
Privacy Badger: Uses heuristic for trackers, a "light" open-source variation of Ghostery.