Used alpha, joven and panasonic before.

Alpha, i bought 2 water heater before, funnily just slightly after the warranty period, spoil. I install one, when spoil, i bought another also alpha, then seriously 1 month after the warranty period also spoil. But maybe that's just my luck.

Joven so far so good. My parent's house use for like 5 years already no problem. Still hot and working, except the thing to hang the shower head one spoil after few years.

Panasonic recently new addition to my house, but only used for about 4 months only. So far so good, except sometimes water really not as hot as i would like it to be. bath at night, sometimes the you turn the heat up to max, the water comes out only luke warm.