No tool deals with guesswork. Careful design and layout is key. The best crash course for building basic skills is in a workshop by the Guild. The machines just cut what they are pointed towards. What you know and what you are secure in comes with work.

So rate the tools

I believe the Makita chain mortiser is the most difficult tool. End grain cutting is rough and sometimes catchy with tear out. the depth of cut is varies in the mortise end to end. The clamps seem to me less than ideal. It's a gizmo.

Mafell chain mortiser is near perfect. Three times the price of Makita. It takes professional commitment to justify purchase.

Makita hollow chisel is the most mechanically controllable. Very robust clamps, x - y controls, stops, flat bottom cuts and drill press feed. Unlike chainsaw machines where the carpenter must dominate the tool and push, with the chisel mortiser the carpenter is not entwined when operating, has distance and good sight. Safety with control. Will cut poplar without problem.

I am not just saying this because I have a tool to sell, I've said the same for years