Comparing distilled vs RO water is a question about the water rather than the machine. Distilled water is close to empty, since almost nothing makes the trip as vapor. Reverse osmosis water keeps a small fraction of what came in, because a membrane rejects most dissolved solids rather than all of them. That gap decides taste and the jobs each one suits.
How complete each separation is
A distiller leaves dissolved solids behind in the boiler, so what condenses is very nearly free of minerals and metals. A membrane is a rejection process rather than an absolute barrier: a healthy element rejects the large majority of dissolved solids, and a small proportion passes through with the water. In practice both produce water far below the mineral content of a normal tap, with distilled sitting lower and staying lower as long as the boiler is descaled.
Taste, and what remineralizing does
Dissolved minerals carry flavor, so both waters taste flat and distilled tastes flattest. Many reverse osmosis systems offer a remineralizing cartridge that adds a small amount of calcium and magnesium back after the membrane, purely for taste and mouthfeel. That option does not exist on a distiller unless you add minerals yourself. If flat water bothers the household, the membrane route is the one with a fix available.
Choosing by the job, not by the label
For everyday drinking and cooking, reverse osmosis is the practical choice: water on demand at a faucet, at reasonable volume, with taste correctable. For a steam iron, a humidifier, a lead-acid battery, a CPAP machine or anything where any residue is a problem, distilled is the answer because it leaves the least behind. Aquarium and laboratory users generally want the lowest possible dissolved content and choose accordingly.
One practical warning about storage
Both waters are aggressive toward containers and pick up whatever they touch, so store either in food-grade plastic or glass rather than in metal. Both are also low in the residual disinfectant that keeps stored water from growing anything, so a tank or jug that sits for weeks needs sanitizing. On a plumbed reverse osmosis system that means the pressure tank; on a distiller it means the collection bottle. Vendors publish stage layouts, membrane ratings and remineralization options on their own product pages.
Questions people ask about distilled vs ro water
Is RO water the same as distilled water?
Not quite. Both are very low in dissolved solids, but distilled is typically lower because a membrane rejects most solids rather than all of them.
Can I use RO water where the instructions say distilled?
For a humidifier or an iron, usually yes and residue will be much reduced. Where a manual insists on distilled, such as some medical devices, follow the manual.
Which tastes better?
Most people prefer reverse osmosis water, particularly with a remineralizing stage, because distilled water tastes noticeably flat.