I've done every one of them... If it wasn't for my calcium reactor I'd have shut my tank down by now.
That being said, on a smaller tank I would likey go with a kalk reactor. With kalk you just add some to the reactor every week or two. I have enough kalk sitting around to last a 50 gallon tank a lifetime...
Dosing is very time consuming when it comes to mix time, more electronics to fail and sourcing the ingredients can be a hassle when you need them. The nice thing is being able to adjust Mg, Alk and Ca separately depending on your salt.