Check out ESH, prices are reasonable / slightly higher then online (shopee/lazada) but they do arrange installer at reasonable rate.
Panansonic, Joven, Alpha are the brands i would trust.

If your house has water pump, you do not need a dc pump. Saves yourself a good 100rm difference at least.
I made that mistake, however it comes in handy when you forget to on the water pump or pump is broken.

I feel all water heater is the same, my 15 year old basic panasonic heater is still working.
Cheapest range with pump is average 400-450rm. A fancy looking unit  may go up to 500+.
If you are good at electronics diy, you can easily replace a unit yourself at your OWN RISK and saves installation charges of 75-120rm.