I used Rete in my PhD work, where I designed incremental view maintenance techniques for the openCypher graph query language (https://szarnyasg.github.io/phd/szarnyasg-phd-dissertation.p...).

Rete is an elegant algorithm that is also quite flexible: one can make non-distributive aggregations, outer joins and recursive traversal work. However, it is quite memory-hungry due to the large state of certain nodes (e.g., join operators). I tried to work around this by using distributed execution, but that made the system very inefficient and complex to operate. I also looked into the TREAT algorithm but found that it is more limited in its functionality than Rete.

For incremental view maintenance, the state of the art has now moved on to techniques such as differential dataflow or DBSP (https://www.vldb.org/pvldb/vol16/p1601-budiu.pdf).