I can't speak for everyone, but my feeling as lose of control is this. If I have this on my own computers nowhere else, I'm the one responsible for everything. Making sure the computers are up and running, up to date etc. If I have it on a cloud based server, all that is done by someone else. I have no idea the
true strengths or weaknesses of your system, employees, what they might, might not have access to. Is there a "backdoor" that a clever hacker might be able to exploit etc. The more you trust to someone else, the more vulnerable you are.
If it's on a cloud system, my server might be running great, but for some reason I may not be able to access the "cloud" for whatever reason. If I need files that are only on the cloud at the time, that might halt production, just depends on the severity of the issue. It never fails to happen for me that things I need are at the one place I can't access at the time.
As to deleting things off the servers once the client no longer uses the service. Is anything truly ever deleted? What lengths to you go to to make sure that even the "ghosts" of those files are taken care of? How do I really know that those lengths are taken? If everything is on my local server, I know exactly what has been done, because I did it.
Now as far as greater efficiency with using the cloud based system. Not really worth it in my case, may be different for someone else, but not in my case and that's all I'm specifically talking about is my case. I only have two computers to update. It's not worth the subscription fees and the values that I place on the drawbacks to using the cloud system for me to use it. I don't use my
iPad for business. I have my main
computer which is a desktop and then my laptop. That laptop can handle everything that desktop can, when I'm mobile, I take that for work on the road. The
iPad can't do everything, so why take 2 things when 1 is more then capable of doing everything?
The cloud is still way to much in its infancy for me to feel comfortable with using it. I may change my mind as I grow and my needs change/grow with that, but not as of right now.