I really enjoyed working at AASP because of its team! They made sure that everything was done perfectly for us during our transition from Office365 (on premise).
Nothing specific came up in regards as far an issues were concerned - but they did go above & beyond what you would expect when moving employees out or taking over their responsibilities within any organization. It is still too early yet into my first year here so i cannot say anything else just then about this service provider other than if it has been good enough already there are no downsides associated at all :) We have had great experience thusfar while transitioning between two different platforms such office 365 vs aws email hosting platform which allowed me flexibility throughout deployment process without much hassle/hassle related concerns etc.