I have an Ariston 4 gal point of use h20 heater under my kitchen sink to reduce/eliminate the delay from my takagi tk2 tankless heater in the basement. It is only a problem when the water is getting turned on and off frequently.

The 4gal heater under the sink has sprung a leak and I am considering replacing it with an eemax instant elec water heater.

http://www.irawoods.com/Eemax-EX95T-Thermostatic-Electric-Tankless-Water-Heater#

Running the larger wire is not a problem, and the space under the sink is currently quite crowded with an RO water filter and the 4 gal ariston. The small size of the eemax is the major appeal plus I already have one that was removed from another house.

Is there any reason NOT to use the electric tankless under the sink (besides needing to run larger wire to the heater)?

Thanks,
Karl