I worked at Mathematica full-time for more than 8 years
Interesting projects focused on important policy issues; wonderful culture; smart, supportive colleagues; flexible WFH policy; employee-owned
Proposal season (late spring/summer through early fall) can be stressful; was getting a bit more 'corporate' when I left; hope this doesn't dampen the generally positive, team-oriented culture.
Advice to Management
Could do more to get staff input/reaction before changing internal processes.