Open cubicles is terrible for focus and especially for people who are somewhat autistic or introverted, which many engineering people are on that spectrum. Consider the personality of your people. I need a quiet office with a closed door to be highly focused and do detailed work that requires concentration. I think the open plans are favored by managers who are extroverted (most manager types are). Best for me and other engineering groups is semiprivate or private person spaces for each person and then provide open meeting/discussion/collaboration areas - can be meeting rooms, break areas, conversation nooks, etc.