I worked on a client site and did not enjoy any of my time with AMS.
Diversity - we have different definition of diversity I guess, top managements are from different places of UK.
Management - they were terrible in people management, hired unqualified people in the jobs (especially managers), and wouldn't listen to the employees.
Communication - they never announced any changes made, and told us we were not following the process, you are a service provider, you need to make sure everyone is updated on what the client asked for
Business model - they had an unrealistic business model, which might sound fancy but just created more workload, which was completely unnecessary.