I've been happy user of ycmd+rtags tandem for a couple of years. A killer feature of rtags me is its ability to run server on remote machine (of course source code must be mirrored too). This allows me to do develop on my weak 4-core laptop and offload indexing to fast 32-core workstation.
Regarding indexing time, all of these tools seem to parse source code using either libclang (C API) or "native" C++ API (RecursiveASTVisitor etc.), so IMHO any difference in indexing time between rtags and cquery should come from such factors as number of parsing threads, database for storing tags, caching etc.
Anyway I'm really excited about cquery and even consider moving to VSCode just because of it (being a long-term VIM user). Reliable "Find references" feature is (IMHO) a must-have functionality for large codebases and currently (thanks to cquery and rtags) is supported much better in modern C++ than in other system languages (such as Go and Rust).
Regarding indexing time, all of these tools seem to parse source code using either libclang (C API) or "native" C++ API (RecursiveASTVisitor etc.), so IMHO any difference in indexing time between rtags and cquery should come from such factors as number of parsing threads, database for storing tags, caching etc.
Anyway I'm really excited about cquery and even consider moving to VSCode just because of it (being a long-term VIM user). Reliable "Find references" feature is (IMHO) a must-have functionality for large codebases and currently (thanks to cquery and rtags) is supported much better in modern C++ than in other system languages (such as Go and Rust).