There are three main options for electric water heaters: the conventional old-school storage tank heaters, heat pump, and on-demand, tankless water heaters. There is also solar water heaters, but they require roof-mounted solar panels. I'm not ready for those yet.
My house is small; about 1,000 square ft. I don't really have room for the conventional storage tank heaters, or a heat pump, which also uses a similar-sized storage tank. That leaves tankless water heaters as my primary option.
I had a gas tankless water heater in my last house and had good luck with it. I never ran out of hot water. The biggest downside of electric, tankless water heaters seems to be the increased electrical requirements. This quote explains the issue: "The average electric tankless water heater needs at least 120 amps to operate and the average household's total capacity is 200 amps."
Since my house is only one bathroom and one kitchen, the electrical sizing requirements might not be too bad. Using EcoSmart's sizing tool, for example, I would need their ECO 24 model which they suggest 200 amp service for the house if okay. Looks like with Stiebel's sizing guide, I'd need their Tempra 24 model, which draws 100 amps.
Matt Risinger likes tankless water heaters and says it's what he uses in his house. He likes installing them inside the air-conditioned envelope so they don't freeze. His is outside at his house however but insulates the water pipes going to it. One comment from a plumber on Matt's video above says: "As a plumber they're awesome. And you should descale (flush out) 1 or 2x a year to insure your investment. Also should have a water filter or softener before the tankless no exceptions." A filter going to it might be a good idea. For what it's worth, it looks like Matt uses a heater from Rinnai, but they don't make electric heaters.
Matt did mention water heaters from HTP on Twitter, saying he has heard good things about them.
This article from WaterFilter Magazine has a good overview of some top choices in electric water heaters. It's so hard to tell from reviews anymore though. That article only includes model from Amazon due to the affiliate link possibilities. There are a bunch of similar reviews from other outlets that seem to exist to generate affiliate links.
Consumer Reports reviewed tankless water heaters and said they work and they all worked about the same:
After weeks of testing, we discovered that all the gas tankless water heaters performed similarly and all the electric tankless were equivalent in terms of performance. “Whole-house tankless heaters are designed to produce a target amount of hot water—3 to 4 gallons a minute—and they did,” says Banta. "We didn't find meaningful performance differences that would cause a consumer to choose one brand over another."
I did run across this Kickstarter for a super efficient, tankless heater from Heatworks. It has 'Ohmic Array Technology'. I'm not sure what that is but I'm a sucker for Kickstarters. Most of the Kickstarters I've bought did not turn out so well. That seems like it would be the case here given different comments I found around the web regarding this product. The comments on the Kickstarter page are pretty bad.