Do the gas ones work? What kind of flow do they give?
The gas work if get one with enough BTU. keep in mind that if you are already on, natural gas at least, and your current supply line to the fixture is half inch it is to small. A tankless will require at least a 3/4 in. supply, also the instant hot water claim is baloney. yes you will get instant hot water at the unit when it fires but unless you have a circulating pump system which will require a storage tank and circulating pump you still have to push all the cold water in the line out before you receive the hot water at the fixture. Also you must install a premium filter in advance of the heater to protect it from mineral build up. Once the heat exchanger starts to build up with calcium it requires a chemical flush and the exchangers can withstand only so many before the require replacement. Always do the math, what is the liftime savings in energy vs. the cost of the unit, new vent ducting, gas line and installation compared to using a regular water heater? For me it made no sense.
I have gas, always have. Dirt cheap to operate. Same with Gas Dryers, if you can get used to the whoomph when they start.
Different flows - pick the one you need.