There are several questions you need to ask about electric heaters.
what is more important to you, Fast Hot water, energy conservation, warranty?
a regular tank type with two elements will give the best recovery of a tank type hot water heater at about 83% efficiency (Cheapest)
a hybrid tank type will give much better efficiency 230% but takes much longer to recover, unless it uses the backup element (expensive)
electric tankless 99% efficient need a lot of power most homes don't have enough unless built with tankless in mind
as far as water heater tanks, they are pretty much the same 6 and 12 year warranties. If you want them to last forever change the anode every two or three years depending on the water conditions and install a expansion tank to help reduce metal fatigue.
Good Luck
George