But I wanted to know other's experience about this subject
"I'm not going to put my toe into the water, because it might be too warm, or too cool".
Don't be a scaredy-cat. Just try it.
I'd do it for you, but I have no need for a mail system, so it would be difficult for me to see if it works for you, and as I said in my previous post, we don't know what your requirements are (five users, fifty users, 50,000,000 users?).
Once you try it, I expect you'll be pleasantly surprised.
If not, just uninstall (or ignore) it and try something else.
It is free software, what are you afraid of losing?
Younger people seem to need their hands holding all the time nowadays.
Where is your sense of adventure ?