I have a 125 gal tank and was wondering should I get another 110 ac or a canister filter for my tank or I should be good right now? Right now I have 2 110 ac, i have a 3" jardini and a common pleco. My tank size is 6ft×2ftx2ft.
With those dimensions, your tank should be approx 180 gallons. I'd say for now your fine with the filtration you have, but will want more later. Larger canisters will generally give you more space for bio media than another AC110 would.
Leaking is a potential risk. But with proper use and buying trusted brands of canisters, I believe it can be minimized to the point of not being a concern.