Pros
Friendly co-workers both in Austin office space and remotely, good flexibility with regards to working from home, even before COVID. Feel that maintaining work-life balance is a priority for managers, at least within my division (MMSS). They were genuinely concerned if I was working more than 40h per week. I also feel that in my division there has been a push towards more active mentorship now than when I started at the company in 2018.
Cons
I think cons have more to do with perils of working with a very large company rather than anything specific to Syneos. For example, the very top management was slow to respond to an issue that ultimately led to extreme understaffing over the fall and summer; however when the go-ahead was given to our department they were able to solve the issue and staffing is no longer a problem. The Austin office is pretty small compared to Raleigh and can sometimes be overlooked, though I think that is getting better.