Hard to say for reliability... though my gut instinct is that the Kenmore (which is made by Electrolux) would be more reliable than the Korean brands.

A better question to ask, though, is what getting service and parts will be like when it does break eventually (because all brands do). And that's why if you're concerned about reliability I'd cross all 3 of those brands off your list. LG and Samsung have proven harder to get support for than the domestic brands. And Kenmore, well... they don't actually make anything. Sears just buys appliances from the major manufacturers with no warranty, slaps the Kenmore sticker on them, and then you're locked into them for warranty service. Out of warranty, getting service from 3rd parties for Kenmore can be more difficult because they don't make tech info available to anyone but their own technicians and there is no way to cross reference Kenmore models to those of the original manufacturer.