Specifically, uBlock is mainly for blocking according to a predefined list of patterns of known malicious content, whereas uMatrix is for blocking all potentially-malicious content and selectively allowing through some kinds of content from domains the user has chosen to trust.
Used it and it was good, as I remember. Later switched to uBlock Origin because it presumably uses less resources and does the job.
They have different purposes. I use both.
Specifically, uBlock is mainly for blocking according to a predefined list of patterns of known malicious content, whereas uMatrix is for blocking all potentially-malicious content and selectively allowing through some kinds of content from domains the user has chosen to trust.