In my experience, with one household member on Maxis Share 48 and another on Hotlink Postpaid 45, virtually zero difference. It is for all intents and purpose, the same line.

Yes same. Hotlink is targetted towards lower segment postpaid while Maxis is for those who willing to pay more and able to buy devices on contract.
As for my previous testing on Maxis and hotlink, same place same model of phone, there is no difference in performance and coverage.

does anyone know if hotlink pospaid can be paired with sim number share for apple watch? plan to port to hotlink from digi due to digi line at my home is terrible..

To my knowledge, only Maxis postpaid can be paired with Apple Watch sim and the Apple Watch sim cost rm18 monthly.
I stand corrected if there is any new info regarding this.

I tried just now, CS refused to direct transfer from Maxis postpaid to Hotlink postpaid. They want me to use prepaid for a month as well.
When I said go ahead, they transfer me to Maxis's retention team
Ended up getting RM20 rebate for my RM79 plan for 3 years, no contract