Sounds like you were more successful then I was on keeping FW tanks. I couldn't keep a planted tank to save my life, the fish uprooted or ate the plants. I spent a small fortune on plants, and decided on the little plugs to let them grow (cheaper) but tender plants were a favorite snack. Once a year I put my fish in buckets, removed all the water (stirring the gravel to remove as much yuck from the very bottom as possible, and at the very end, cleaned the gravel with a vacuum gizmo, I did just drop in chlorine remover for the water replacement, and then it was time to scrub the rocks and décor of algae... it was an all day, way into the evening job. My back would be screaming by the time I got it finished.
SW tanks I never had to do that, I have never had to remove all my fish (chasing them around half a day to catch them) and put them into buckets. I have never, not once in over 15 years had to vacuum the substrate, the CUC takes care of that. The only time I ever scrubbed a rock was once when I had hair algae. I never heard of a water change until I started keeping a SW tank, so a water change for FW...never did that.
I agree, the only things SW and FW tanks have in common, are the fact they both are tanks with water in them. I never cured live rock, not once...I have always purchased cured rock that I hand picked at the LFS. I had replaced 3 sets of lights (a sad expensive lesson) before I got the right lighting for keeping corals. The test kits and such was something to learn, but I never considered it difficult to do. I worked much harder and suffered more grief keeping my FW tanks, then I ever did on the SW ones... LOL...But then again, my most expensive FW fish was $25.00.