Tank type (all natural, high tech, white sticks or algae covered, etc..): High Tech

Coral types kept (SPS, LPS, sofies, low end, high end, etc..): Mixed Reef, SPS, LPS, Softies

Years in the hobby: 4.5

I was always manually dosing my tank with decent results. But I was always a little worried of over dosing. I heard numerous stories about how a calcium reactor is much more stable and provides more nutrients than manual dosing, as well as cheaper in the long run. 

Manual Dosing 

Pros

No expensive start up cost.

Cons

Dosing on a daily/weekly basis

Difficult to dose smaller elements (Strontium, Potassium, etc...)

Costly month to month basis. 

Calcium Reactor

Pros

Provides a more stable dosing method (Continuously dosing in small amounts)

Doses small elements not often found in manual dosing.

Little to no cost after initial purchase

After dialing in little to no maintenance required

Cons

Can lower PH drastically if no fail safe (Apex)

Expensive start up cost

Bulky equipment in sump or out of sump

I must say after I dialed in my reactor i saw increased growth, color, and polyp extension. Nothing is better at building corals, then corals themselves. What I mean by this is, that the media inside the reactor is essentially dead coral, with calcium, alkalinity, magnesium, strontium, potassium, etc etc... IMO this created the most ideal setting for coral growth and development. 

210 display, ~400g total water volume

sps with a few mushrooms for my wife

about 15 years with aquariums.

It's all about what is a convenient way for you to keep the water parameters stable.  I say convenient because, if your setup is too complicated or time consuming, your most likely not going to maintain it long term.  You can find many articles promoting and demoting each method out there, so pick one that is most suitable for you.

Currently I dose BRS alk, ca, and mag via dosing pumps controlled with an apex.  I also have my top off water running into a kalk stirrer.  This set up has worked for me for years and fits my schedule.  I mix up more powder and add to my 5g dosing containers as needed and do a weekly dump of kalk into the stirrer. I also preform 1 or 2 water changes a month.

Manual dosing is defiantly something you want to move away from, as soon as your budget allows, for the amount of water you are keeping.  It will greatly help with the stability of your system.  As with anything new, you are likely to encounter issues with the learning curve, but just stick with it. Good luck and happy reefing.

-Alex