Vantaggi
One manager was great -- all the others for the contracts turned out to be terrible.
Svantaggi
The business model seems to be to overpromise and underdeliver, leaving the Instructional designers (ISDs) to fend for themselves. I worked for a few projects, and the POCs/managers for each contract were all over the place - some were on top of things, some were not-- being out of touch, dropping the ball, or saying whatever they could to make the client happy, whether or not their promises were realistic, making things unnecessarily difficult for ISDs.
Their goal is to quickly slot in people for contracts, whether or not they are a great match. This does not benefit employees, teams, or clients, and it can be a really big problem for everyone, but Insignia don't take responsibility for the problems they create. Also, contracts are offered on short notice and infrequently, so you can't really decline, since who knows when the next offer will be.
One note on benefits: they offer a 401K contribution, but it's a "match" of 25% of what the employee contributes, which is capped at 4%. In other words, the Insignia contribution is capped at 1% -- virtually nothing. It says a lot about how much they value employees.