The process was pretty relaxed when I did it. But, again, this was 2011, so probably things have changed. Felt like it was a lot more about fit and trying to figure out which team/project I'd best slot into than it was about making me prove my abilities (though, they already knew my credentials in that department).

I was full-time remote for the entire ~4 years I was at Mozilla. It has upsides and downsides. Upside was an incredibly easy "commute" from my bedroom to the spare bedroom I'd converted into my office, and general lack of early-morning meetings (so I could keep the later hours that suit me a bit better). Downside was isolation. Even with communications channels available, and in-person gatherings a few times a year, remote work is isolating. It's also worth noting there is, or at least was, a ton of variance in what the experience was like depending on which org/team/project.

These days I work for a company that has an office around 20 miles away, but I work from home at least a couple days each week, mostly going in when there are meetings I want to attend in person. That seems to be a better fit for me.