Let me first list down their feature differences for u, everything else not listed here are the same 
1. 516 has cold water
2. 516 has auto up-down water tap
3. 217 water tap is taller, easier for certain ppl to fill water bottle
4. 516 preset volume (120, 250, 500 and 1,000ml), 217 only (120, 250, 500ml)
5. 516 has auto internal and water tap sterilisation function (flushing with hot water), 217 has neither (But both have UV sterilisation for water tap)
6. 516 can be self-serviced (DIY change filters every 6 mths) cuz it has the functions in item 4 above, 217 can only be serviced by our technician every 3 mths

Then their price difference is:-
217 - Rm3,030 = RM1,500 + RM1,530 (Discounted price if buy 5 yrs in advance, if buy year-by-year Rm360 x 5 yrs = Rm1,800)
516 - Rm4,200 = Rm50 x 84 mths

So really up to u whether worth to pay extra Rm1,230 for the extra features, i think the more important ones are the auto sterilisation functions and self-servicing feature 

No need, other than the few preset volume, both models also come with another button for continuous dispensing for 3 min non-stop

The promo ends 30 June ya

The 217 filters replacement are similar to 516, but since 217 isn't equipped with sterilisation functions, it'll need a separate device to help flush it's components, so that's what our technician will do when he visits every 3 mths 

The filtered water is perfectly safe to drink directly, but according to chinese tradition, some still boils it in case their babies couldn't take the "coldness" 

There's no internal UV sterilisation, UV sterilisation is only for the water tap (cuz it's exposed to germs in the air, but cannot be flushed with water otherwise ur kitchen will be all wet  ), internal pipes will be cleaned by flushing with hot water every week instead

Straight into your drainage pipe

Both water in and out is connected directly to the in/outlet under your sink

210 Rm40, 518 Rm50

Main diff:
1. Smaller size
2. No cold water
3. No moving tap

The rest are mostly aesthetics (mood lighting, buttons position etc.)

518 tap can be install straight or on the side horizontally but is fixed once installed (due to the square shape design), vertically the tap can auto up-down either way u installed it

210 tap is fixed both vertically and horizontally

Yup, 210 comes with all other functions of the 518, auto internal sterilisation, auto tap sterilisation, s/steel internal pipings, customised volume, favourite settings etc.

If don't need the cold water from 518, good enuf to go for 210, unless u like the design or color of 518 

How the entire process actually works for LG? i received message 4 weeks ago to confirm the delivery address and i have submitted immediately. And waited till today.

SA gave me LG number to call and said will follow up but never response to me automatically. Every time i have to keep asking him for a reply and answer is always 'i will have to ask LG'. Even i called LG also no confirmation can be given.  i called until i almost get fed up.

I dont think is SA problem as SA cannot control the delivery. Is is solely LG problem. i think they mess up the delivery.