Which is better 48v with bms or 4x 12v with bms each connected in series ?

Which is better 48v with bms or 4x 12v with bms each connected in series ? I have 4x 3s10p that has a 10amp bms each. Just wondering if it's better to run those in series to get 48v 40amp or reconfigure it to 12s10p?

Firstly if you series them up, it will be 48v still with a 10amps bms limit not 40a...not sure if this is a mistake or misunderstanding.
Series connected bms's can fail if one shuts down and the sees full pack voltage not the 3s it was designed for.
So you're better off reconfiguring to 12s with one 12s bms ( imo, others may disagree).

apologies i meant 10amp. i will reconfigurenthem. any suggestion on a a good cost effective/affordable bms? are the ones from bangood good enough?

Cheap Chinese bms's are sold by all the various online vendors so there's no way to say 'these ones' are good or not.
Try ordering from:
https://www.litechpower.com
They have a large selection and quality seems to be good in my 2-3 purchases through them. But they are more expensive than say aliexpress. Millions of cheap bms's there, select one with almost double the amps you need if you do, cause theyre not always up to their rated specs.