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.

Very fast heat up and support is good

Basically it's outlined here - https://www.st.gov.my/en/contents/publicati...r%20Systems.pdf

The mandatory item:
1. A 10mA RCD [dedicated for WH circuit only] must be installed.
1.1 Failure to install 10mA RCD and fault condition occur = results in ending up on the news https://www.malaymail.com/news/malaysia/202...c-shock/1896447

2. Pull direct 4mm LNE cable from DB box to WH
2.1 Use good cable with mfg name, spec (4.0mmsq) and with MS2112-3 SIRIM certified printed on it.
Many elcheapo cable either no name, undersized, or for car use (low voltage PVC Auto).
Good cable come from Mega Kabel, Caramay, or any of the cartel here http://www.mcma.org.my/member.htm will be OK.

3. Insulation of the hot copper pipes is recommended for heating efficiency (not mandatory).
Superlon foam tube very cheap 2m only RM2 or so only.
Superlon can stand up to 85-105C. More than enough for WH hot pipe. See https://www.superlon.com.my/wp-content/uplo...alogue-2019.pdf

4. For the water piping connection at the WH can use a short flexihose (Hokah recommended) to connect them to permanent piping so easier to remove the unit if there is a need to service it or replace it next time (as compared to hardcoded permanent installation).
4.1 Can also install a service valve so you can off the water inlet (input) to WH in case it leak or other malfunction.

Also make sure that the storage water heater is being installed with:
a. 2 Isolation Barriers (at water inlet and outlet) - to prevent electrocution
b. Pressure Relief Valve (at water inlet) - to prevent storage tank from being over-pressured (which might cause it to rupture / leak), and to facilitate water drainage during servicing

If I am not mistaken, this will be a compulsory requirement set by SIRIM and Suruhanjaya Tenaga for all SIRIM-approved brands to be pre-installed with these 2 items soon.

By far, storage water heaters market leaders like CENTON and JOVEN already followed this ruling. But just double check during your installation and make sure these 2 items are being fitted, just in case the brand u have bought doesn't have them.