Pros
One of the best cultures among investment banks. International, diverse. People treat each other with respect. Very collaborative (every deal is cross border and you are always working with different offices). The firm is owned by the partners who actively work there. While compensation may not be bulge bracket, it is still good, especially given the better work life balance which can (sometimes) occur. Juniors are properly mentored and cultivated.
Cons
BDA has come a long way over the past decade. It is now seen as a premium advisor. Still, there is some lacking perception from potential clients when BDA is pitching for large deals. BDA has a very close partnership with William Blair. Because "BDA" is a different brand name than "William Blair," some clients may not feel they would get the "William Blair" experience if they hire BDA. More should be done to align perceptions of the brands.