I already did the hardwork for you why randomly experiment? Here my list stick to it and you will have alot fun with spay. Once awhile I will randomly try new shops to update my list.
So refer to my list you will know how often it fail so failure usually due to terminal.
All this is based on my actual usage and experience
Here also success rate of merchant bank terminal
Public bank - failure rate 90%
Hong Leong bank - failure rate 80%
Maybank - failure rate 20%
CIMB - failure rate 0%
Ambank - failure rate 10%
Aeon big - failure rate 0%
IKEA - failure rate 0%
Giant - failure rate 0%
Guardian failure rate 0% but only staff attitude problem
bHP failure rate 0%
Shell failure rate 80%
Caltex 50%
Starbucks 0%
Cafebene failure rate 50%
Petronas failure rate 0%
Macdonald 5%
Coffee bean failure rate 0%
Speedmart 99 - failure rate 50% with minimum
Familymart - failure rate 0% no minimum
My news - failure rate 100%
Mr. Diy - failure rate 100%
Sin tuck woh hardware - failure rate 100%
Hardware store near My house - failure rate 100%
Machinery shop near Mt house - failure rate 100%
Hardware shop near my work - failure 15%
Pet shop at giant kelana jaya - failure rate 0%
All IT hypermarket the curve - failure rate 100%
KFC - failure rate 70%
*Vendor that failure rate 100% can use physical card but not spay
Updated 5.2.18
Just to inform I've been to a few mynews that accepts spay without minimum amount. There are still some that don't accept which I just avoid.
Also Mr. Diy in aeon big wangsa maju accepts spay without minimum purchase.
All of those I asked to use paywave instead of spay.