180mm MT5 on the 26inch giant STP: (this has Shimano zee levers).
180mm MT4 on the 26inch giant trials team:
203mm MT trail sport on the 24inch Marino.
I also run a MT7 on the rear of my 27.5inch enduro bike with a 203mm rotor.
Of all the brakes, the MT trail sport is my favourite. They are sold as a pair, the front is 4 pot and the rear is 2 pot. I run them the opposite way around for more power at the rear and a lighter front end. I also run jitsie pads in the rear.
Crucially though, I’m a relatively heavy lad, the mt4 on the giant trials team which I run a smaller rotor with bigger wheels works absolutely fine for me. Great modulation, lighter than a MT5/7 calliper and plenty enough bite to hold when the back wheel isn’t bang on a ledge / rail. It’s also running standard magura pads.
A couple of questions to consider the answers to in helping you make a decision:
1. what type of riding are you doing? Natural, TGS or street. Or maybe a mix of all?
2. What bike are you looking to put the brake on? What size wheel?
3. If you are more than 15 stone I’d for an MT5 or 7.
hope that helps