Agree with LifeSpeed on this one,
RO water does not taste "flat". There is a lot more to it than a simple blanket statement. RO water is also not "Very aggrsssive". RO water can taste flat, and it can be mildly agressive. Most modern RO systems use a simple GAC post filter to "sweeten" the waters taste. Other companies will add a remineralization filter to enhance the flavor, but most RO systems do not need this. Most bottled water companies use RO to make their water then simply add a few trace amounts of minerals to "enhance" the flavor, but most people could not tell the difference.
Softeners do not add common salt (NACL) into the water, they add sodium. The chloride levels basically remain the same unless you are also using some sort of Anion resin for sulfate, tannin, or nitrate removal, then you will see an increase in the chloride levels too.
My suggestion, Softener for whole house, RO for drinking cooking, ice maker. The RO water as a general rule should not go through metal plumbing because it has the potential to damage it over time. A simple calcite post filter can be used to lessen this potential and can also be added to add flavor if the water does not taste like you think it should.