I have been in this hobby for about 30 years. Most people experience fish loss when they first set-up their tank. This is often due to lack of knowledge and a tank that is "unseasoned". Many hobbyist will tell you in the first year you may lose two fish for every one that survives. Currently, I have a Niger Trigger for five years, a Sohal Tang for 4 years, a zebra damsel for 5years and a yellow tang for 4 years. It has been years since I have lost a fish. I recently moved all the fish into a larger aquarium and lost nothing. The fish were outgrowing the tank they were in and I will eventaully need to get a bigger tank than the one I just upsized to.
I beleive a tank with live rock is the way to go. The fish seem happeier and healthier. The best filter equipment tto have is probably a refugium and/or good protein skimmer.
If you do your reserach before setting up a tank you can minimize your losses early on. Most people when they first get in the hobby (including me) rush to stock their tanks only to be frustrated when the fish start dying..
There are certain salt water fish that are difficult to keep as they do not do well in aquariums...Moorish Idols are a good example.
Just my opinion.....I do not claim to be an expert.