PRO: Most of my transactions have been smooth, and have been delivered very promptly. A lot of payment options available which should suit almost anyone's preference. Discount vouchers are also abundant for added value. Of course, delivery is free for orders above 1k, which is always nice.
CONS: On instances where issues arise, Lazada's customer service isn't exactly world-class (see example below). Previous experience with customer service includes poor response time, canned responses and broken expectations. Aside from misrouted delivery, I have also encountered cancelled orders because of items sold but didn't have stock, 1 occurrence of DOA item which was not replaced (gave refund despite me specifying I wanted a replacement, they cited merchant has no stock when in fact there is), plus 2 other occasions in the past where delivery date was past the promised date. Not customer service related, but noticed some items listed with bloated prices so it would appear you are getting them on sale even if it's just the same as market value.
OVERALL: Generally pleasing total shopping experience which they do get right most of the time. Customer service needs improvement.
Lazada if you are reading, use this as reference, Order 393591522. Didn't deliver item, courier misrouted. Opened a ticket to get fixed, they said they took care of it but in reality didn't. Now they are no longer responding. I have another pending delivery, that too has breached delivered by date which they set.
I sincerely hope you go out of business because you screw your customers who need help and leave them in the cold.
[UPDATE: Issue has been resolved but the overall experience was still poor]