i dose zeo vit and i love it. i dont use there four part but i use there coral vitalizer, pohls extra, b-balance, pohls sponge power, and potassium iodide flouride. my colors look amazing and now im going try making my own dosing chamber for pickling lime.
All of the methods you mentioned above are used for different things. Running carbon helps rid the system of any toxens that might be present and also helps the clarity of the water. Dosing vodka is to help lower Nitrates in your tank. Running a calcium reactor or using some sort of 2-Part dosing method is used to help maintain the right clacium and alkalinity levels in your tank. So it depends on what you are trying to accomplish as to what you should do. Also as Agsansoo states more info about your tank would help. Tank parameters, size, inhabitants and so forth.
Please provide some system details please.