I've tried them all. Trackpad, trackpoint, trackball, all of them. I keep coming back to a mouse. Everything else is either frustrating and finicky, or it induces RSI after a few hours.
I detest the trackpad on my Windows (Linux soon) laptop, so I have to use an external mouse with it, but I use the "magic trackpad" on my personal and work macbooks including external ones without issues (except if I have to drag something very far; this three finger drag seems to make it nicer although it wouldn't work if I needed to make sure not to let go like when dragging files around). Just wanted to point out that there's a big difference.
Did you try a mousetrapper?
What worked for me is “logitech lift”, one left handed the other right handed. When they are connected I set up my Mac to disable the trackpad.
That + sport and standing desk, did wonder to me.