Pros
It is truly a global franchise and promotes its employees to think globally. At least with my manager, he/she tries to ensure employees are satisfied and have a good work/life balance, particularly since compensation is constrained. Generally (but especially applicable to large firms like HSBC), if your manager is competent and fights for his/her staff, then employees become more motivated to succeed.
Cons
Where do I begin...first off technology/IT infrastructure and staff needs massive improvement. Overall, employee turnover, across all levels of the group, are extremely high. Part of the reason is the lack of accountability and high amount of strategic changes, which prompts management shake ups. The big downside of being a global firm is that executives in London do not fully understand or appreciate the challenges facing the local businesses. And bringing in management from London is often not effective, especially since these managers are temporary (stints last 2-5 years) and does not instill any sense of stability.