Losing employer insurance, where should I look? - what worked for you?

I have 12 weeks left on my current insurance and I am comparing options. I do not usually post, so bear with me. I think my income this year might qualify for a subsidy. How fast did coverage start?

Losing job-based coverage usually opens a special enrolment window, so check the deadline on the official marketplace site. I missed it by a day once and regretted it.