2) Do we pay not too much fees?
You're paying attention to the wrong number. you're worried about 4% when you should really be concerned with net income.
go to a 0% pool, and figure out how much you make, and go to middlecoin, and figure out how much you make after 3.8% fee.
you will net more from middlecoin. i frankly don't care if middlecoin takes 10% if they're giving me a higher net return.
I don't expect any tech support or uptime from a 0% pool. you get what you pay for.