Updating this as I flew this a week ago.
Check-in at KUL: Although there were 2 counters opened for Business/*G, I had to wait about 15 mins in line with just 1 pax ahead of me. For whatever reason, the 3rd party agents had 2-3 agents working on an issue related to some ticket of a pax. The only counter still serving pax took some time and was also being disrupted on/off dealing with that same issue. In general, it was friendly but very inefficient. There seem to be a lead station manager who did nothing to improve the situation (such as they could have asked us to us the next available economy counter).

Lounge: As indicated on the *A website, Plaza Premium is the lounge used. Just note this lounge is at the Main terminal (while the plane departs from the satellite terminal). The lounge is also a Priority Pass/Bank pass lounge, so it is totally packed. They do reserve an area for airline guests with all included drinks from the bar - it's indicated on your boading pass. However, this was initially not informed to us that this was a reserved area, until I went to the bar and found out. It is however, very mediocre area/food. I hope that all the airlines using this lounge will find something better at the satellite terminal. (The best lounge now is those flying Oneworld airlines to use the MH ones).

Boarding: Was on time, and orderly with *G also being invited to board after Business (which was close to empty on this leg)

Seats: Not sure what crazy algorithm is used but I initially booked with the middle seat free, but upon check-in was told the middle seat was taken, which turned out to be correct. Changed seat on board with the middle seat pax and sat next to my travel companion. The flight on this sector had quite a number of seats open.

Interior condition: My first time flying ET - and on this 787 plane, I had never seen such a beaten up interior. Seats were basically falling apart - they were all in very bad conditions - parts falling out, seat fabrics torn, magazine pouches at the bulk head hanging on 1 hinge, etc.

Onboard service: Crew in general was OK - friendly, but more interested in chatting within themselves during boarding but friendly during service. Quite impressed with the offerings which seemed to be much better compared to both MH and SQ - as alcoholic and different choices of soft drinks offered unlike the limited choices from MH/SQ. Was offered a bread sandwich which was actually good.

Punctuality: For whatever reason, although boarded and left the gate on time, it took close to 20 mins wait before we could take off from KUL, therefore I guess the padded timing. Arrived close to the scheduled arrival time in to Singapore.

After this, would I fly ET in Y for a longer sector - my answer would be no. I just found the legroom to be quite tight and the seat condition seems to be bad. For this sector, if the timing works for me, with the reasonable price, I would do it again.

For photos, feel free to see them on my insta.

Cheers!