yup agree with you on Samsung SC (mine at Wisma Bentley)
Few years back I own a Galaxy Note 2. Warranty expired, but out of courtesy they replaced the motherboard. Bring home, next day mobo died again. Return to SC, they replace motherboard 2nd time. Go home, next day died again. SC say something frying up the mobo at night, please return cable and charger. One shot they replaced all 3 items, mobo for 3rd time, charger and cable. FOC. Phone working until now. At one time there is echo, bring back to SC, they found out the tiny gasket near the mic missing, they fix it back FOC again.
Also sent a Galaxy Mega 6.3 charging port problem, they replaced in less than 30min. It was under warranty. FOC. Very nice SC plenty of devices to play with. Nice sofa and free drinks.
No experience with Mi SC yet.
My Mi4i used for 11 months ..no problem, sold it and changed to RN3 now. Hopefully never need to visit Mi SC.
I think we agreed with half of samsung price we pay for their services.
But xiaomi is not bad with their super cheap price with super specs.