I think J&T cause problem depend on the location or district distribution center. So far I got no problem with J&T at my area and it is better than Postlaju. Only experience 1 time during Shopee online sale where the few items were arrived but not deliver to me but keep overnight at the business premise until Day 7 i decided to go self collect rather than wait. This is during first MCO implementation and my area is green area and distance only 3KM away.

From my observation for all my items purchase from Shopee deliver by J&T, if your item arrived at your area J&T distribution center at early morning before 9am mostly it will deliver on same day but if the package arrive after that, mostly will be deliver next day.

Conclusion, if more than 3 days still not deliver, better go self collect because your package might be stack with new parcel and might delay. If you are willing to wait, then it is fine.

My worst experience is with Postlaju. They assigned their small parcel to their part time agent and few times my parcel is not receive but is stated in Shopee my order has delivered with and receiver is unknown person. Complaint to Shopee and requested for refund but the Seller dispute it. Shopee check with Postlaju and come out another name and IC unknown person. It delay me 3 weeks until i decide to go to Poslaju office and create havoc and complaint. At the end, after half hour later, 1 young malay guy (not wearing Postlaju uniform and wear slipper) came quickly pass all the parcel and leave immediately with his motor. After that no more issue of missing parcel but I will try to avoid Postlaju except if no other option available.

I also try to avoid DHL ecommerce as well. Their delivery from my area distribution is fast but collect from seller took few days after seller flag DHL to collect the item from them. Then they keep in their main distribution center for another few days to a week before ship out to my area distribution center. It took around 10 days to arrive after collection.