Pros
My experience is that Trinet has a bright, inquisitive employee population. Most of the people I have encountered are genuinely nice and pleasant to work with and all strive for the best outcomes whether its related to the clients or internal interactions. Flexible working environment which given Bay Area traffic is perfect. Direct managers are responsive, supportive for things within their control. Great benefits.
Cons
Some of the departments seem understaffed or priorities not aligned with overall mission, if you have a problem, it could take weeks for resolution or traction; often requiring an escalation to obtain a response. There are a ton of resources to do your job, but finding info on the Intranet is cumbersome. Too many internal systems to access data. Not enough resources towards supporting larger customers HRIS needs which prompts them to move.