I'm getting ready to replace my ancient water heater and wondering whether it makes sense to get to a model with a (edit: 316L) stainless steel inner tank instead of one with the standard glass-lined tank. I like the fact that these units require no anode rods and theoretically will never leak if plumbed with an expansion tank. Is the upcharge to go with one of these worth it, or would I be wasting my money because electric water heaters typically fail catastrophically in ways other than the inner tank leaking?
The key word you used is "theoretically".
Stainless steel is not all the same. Is it 304 or 316 stainless?
It should last much longer than glass lined but still not forever.
If you can afford it, for longevity, I would eliminate as much steel or galvanized steel as possible.
Good luck on your project!