So, summarizing, pros/cons as I see them for my usage:
Iridium/Chromium pros:
- ability to create exception lists by domain for JS, images, cookies is built in in a way I know of, without adding plugins or extensions that might get less code review or bought by a malicious maintainer w/o my knowledge (maybe rare, but has been reported for some).
- if I switch platforms and continue with my current usage habits I am not forced into DoH (yet?).
- has pledge/unveil support (limiting risk today on a platform I trust more to do that right, with fewer privilege escalation bugs etc and less complexity/knowledge required than SELinux etc. (many fewer zero-days at the OS level).
Firefox pros:
- avoids mononoculture (a big one).
- Maybe has fewer zero-day bugs than Chromium or the older Iridium (at the user and application level only).
- will probably have OBSD pledge/unveil support in the next OBSD release or sooner.
- Does not send metrics (or other tracking) to Google in the current version (true? I actually don't know, I might have read some accusation that I didn't investigate)? (Does not apply when comparing to Iridium, but that seems to lag Chromium bugfixes by some months.)
I plan to think about weighting these for myself. Corrections welcome on whatever I have missed or forgotten. Thanks much for the discussion.