They do what they do because that's what they've been doing and clients with hire them to burn budgets.
Pros
Some diversity in project work. Some, but very few opportunities for leading projects - there are mostly cons. not sure if this is a pro or con but anyway, clients let you do whatever you want - they are NEVER engaged in what they hire you to do - Battelle doesn't deal with this well.
Cons
They are way behind in their capabilities and the "company" (i.e., mgnt) has no interest in catching up. There is no support in anyway for conference travel, writing proposals (you are required to write proposals on your own-time), maintaining a professional network, publishing... list goes on. There is literally no goal to improve research capabilities and there is no way to get equipment to do project work unless you buy it with your own salary. Staff are "encouraged" (i.e., forced) to use their vacation hours to complete poorly managed and underfunded project work. Many project managers require their staff to user their own money to support project costs (e.g., travel, project supplies, ...even equipment!!!!). Line manager literally doesn't know the names of his staff or their job categories. Quality control creates lots of awkward red-tape. Imagine all documents going through multiple reviews before leaving to your clients, including emails and meeting agendas. Each review costs your project money.